Macy’s Herald Square Sept 10th 8 PM: “Real Housewives of New York City” star JILL ZARIN will host a shoe shopping party at Macy’s Herald Square. Stop by, its for a great cause!

Fashion’s VERY big night out, 2009.

Mercedes-Benz Fashion Week – that very exclusive, invitation-only (sorry, you’re soooo not invited) fashion takeover of New York City – kicks off tomorrow morning. But, don’t feel left out, because tomorrow evening it’s “Fashion’s Night Out,” an open-to-the-public fashion invasion of epic proportions. Starting around 6, with most participating stores open until 11 p.m., think celebrities, designer appearances (Oscar de la Renta sings at his Madison Avenue store), free stuff, lessons (cha-cha at Kate Spade?) and all-around wacky happenings (ping-pong with Stuart Weitzman). More than 700 retailers in the metro area are participating, along with events in other fashion capitals around the world.

“It’s kind of a once-in-a-lifetime type of thing,” says Council of Fashion Designers of America executive director Steven Kolb. The organization, along with Vogue and NYC & Company, New York‘s tourism/marketing agency, created the event to rev up sales and consumer confidence. “This is an opportunity for people who don’t get to go to fashion week to engage in it in real time,” Kolb says, adding, “It’s going to be a blast.”

Indeed. Champagne and cocktails will flow, DJs will spin, and whole shopping neighborhoods will throw block parties.

A charitable element adds balance, with 40 percent of the proceeds from the sale of official FNO T-shirts going to the National September 11 Memorial and Museum at the World Trade Center. And a citywide clothing drive benefits the NYC AIDS Fund.

It’s “a fun way for everyone to come together and show their dedication to the community,” Tommy Hilfiger says. “It also happens to be a great excuse to go shopping.” Amen.

But, so many fashion happenings – way too many to print. So get the details at fashionsnightout.com. We’ve listed some highlights.

Maybe we’ll see you there.

DESIGNERS

5 PM: DONNA KARAN will kick off the evening in her new shop at Saks Fifth Avenue.

5:30 PM: ZAC POSEN will use dresses as a canvas and paint one-of-a-kind looks on model Anna Cleveland in the Fifth Avenue windows of Bergdorf Goodman.

6-7 PM: ELI TAHARI will pose for Polaroids with his clients at Saks Fifth Avenue.

6-7 PM: CAROLINA HERRERA with make an appearance with magician Mark Mitton (two shows 6:15 and 6:45) at her newly redesigned boutique on the third floor of Saks.

8:30-10 PM: “Project Runway” winner CHRISTIAN SIRIANO will be at Payless (Lexington and 58th Street) and will be “fiercely” happy to autograph purchases of his first shoe and handbag collection.

7 PM: MICHAEL KORS will make a grand entrance, complete with klieg lights and Debra Messing on his arm at the Broadway entrance of Macy’s Herald Square to launch his new fragrance, “Very Hollywood Michael.” Afterward, he’ll head into the fragrance arcade.

5-9 PM: OSCAR DE LA RENTA will mingle with visitors at his Madison Avenue boutique until 9. Then it’s invitation-only as de la Renta plans to sing for his guests.

CELEBRITIES

7 PM: ASHLEY AND MARY-KATE OLSEN are guest bartenders at Bergdorf’s restaurant on the seventh floor, whipping up some new libations.

7 PM: SIENNA AND SAVANNAH MILLER of Twenty8Twelve by s. miller, will be at Intermix, Soho.

7 PM: CHARLIZE THERON, the face of Dior’s J’Adore Fragrance, will be at the Dior Flagship Boutique on East 57th Street.

7:15 PM: VICTORIA BECKHAM will be at Bergdorf autographing FNO T-shirts.

7:30 PM: EMMANUELLE CHRIQUI, Sloan on “Entourage,” will be at Kiehl’s flagship at 13th Street and Third Avenue, where you can also sing karaoke for a chance at a $1,000 shopping spree.

8 PM: KATE HUDSON will be at Stella McCartney‘s West 14th Street boutique.

8:30-9:30 PM: JUSTIN TIMBERLAKE AND TRACE AYALA, founders of the William Rast line, will celebrate a new pop-up store in the SnAKs cafe at Saks.

LATE NIGHT: HUGH JACKMAN is slated to appear at Jeffrey NY and just may sign FNO T-shirts.

MUSIC

5-ISH: A musical performance by the cast of “Hair,” Macy’s Queens Center

6 PM: Catch a performance by Epic recording artist Howie Day on the second floor of Bloomingdale’s, 59th Street.

9 PM: Grammy winner Estelle hosts a gathering at Rachel Roy’s new pop-up store on Spring Street. Lady Bunny will entertain.

9:30 and 10:15 PM: Catch buzz-worthy singer-songwriter Caitlin Crosby at the Tommy Hilfiger Soho store. Hilfiger will be there, too, and you can get a signed copy of his book “Iconic America” with any purchase of $50 or more along with a signed copy of Crosby’s CD “Flawz.”

9-10 PM: Singer Diane Birch will perform at Diane von Furstenberg‘s Meatpacking District store.

LESSONS, DEMOS, EXHIBITIONS

6-11 PM: Cha-cha lessons on the city streets are the night’s activity at both Kate Spade stores (Fifth Avenue and Broome Street). To help you shake your inhibitions, they’ll be serving up Havana highballs.

6:30-8:30 PM: Nora Ephron will introduce a special reading by Rosie O’Donnell of Ephron’s new play, “Love, Loss, and What I Wore,” at the Giorgio Armani boutique on Madison Avenue.

7-8 PM: Fitness expert Tracy Anderson (she trains Madonna) will host a fitness seminar at Diane von Furstenberg‘s Meatpacking District boutique.

7 PM: Well-known nightlife photographer Patrick McMullan will be on hand with an exhibit of his photos, some of which will be sold at a silent auction. And get a signed copy of one of his books with any purchase made on the third floor, Lord & Taylor.

7-8 PM: Learn to runway walk with top models who will watch you strut and analyze, and meet designer Alexander Wang, who created the FNO T-shirt, Barneys New York.

9 PM: Blowout lessons at the Oscar Blandi Salon on Madison and 55th, accompanied by Bellinis, Champagne and hors d’oeuvres. Call to preregister (there’s still room): 212-988-9404.

GIFTS WITH PURCHASE

6 PM: The first 25 customers who make a purchase at Stuart Weitzman‘s Columbus Circle or Madison Avenue store get free leopard rain boots, valued at $98.

6-10 PM: Get a free serving of yummy 40 Carrots frozen yogurt with any purchase, seventh floor, Bloomingdale’s 59th Street

6-11 PM: At Tory Burch’s block party in the Meatpacking District, there will be barbecues, professional photos of all the guests and a fab limited-edition camouflage tote with every purchase.

6-11 PM: Famed fashion photographer Arthur Elgort will take personal portraits of Dior clients at the flagship boutique. You need to spend big – $2,500 – but makeup artist Ricky Wilson, who has worked on the likes of Sharon Stone, Leighton Meester and Emmy Rossum, will do your makeup, and top stylist Sally Lyndley will help dress you for the photo shoot.

FUN AND GAMES

6 PM: Shoe designer STUART WEITZMAN loves ping-pong and might just play you from 6 to 7 p.m. at his Columbus Circle store and from 8 p.m. at his Madison Avenue location.

7 PM: Bravo “Top Chef” host PADMA LAKSHMI will judge a cook-off with designers Cynthia Rowley, Edward Bess, Gilles Mendel, Lela Rose, Naeem Kahn and Peter Som at Bergdorf Goodman.

7-11 PM: So you want to be a model? Try out for a coveted spot in the alice + olivia fashion week presentation. At the West 40th Street store, they’ll do your hair, makeup and wardrobe before you pose for a professional photographer. Photos will be posted on their Web site, and a winner will be chosen the next day.

8 PM: Vogue editor at large ANDRE LEON TALLEY hosts a life-size version of the new game “Fashion Rules,” with players Donna Karan, Bergdorf fashion director Linda Fargo, fashion guru Robert Verdi and a few lucky customers at Bergdorf Goodman.

FREE SERVICES & STUFF

6-11 PM: Free gift bags at Korres stores in Manhattan and Brooklyn are filled with the brand’s bestsellers, and guests will be served healthy cupcakes and “detox” cocktails infused with the skin-care line’s natural ingredients. You can also prebook complimentary makeovers by visiting korres.com/news.

6-11 PM: C.O. Bigelow, the oldest apothecary in America, will be handing out free Mentha Lip Shines, a top-selling lip gloss, as well as drinks from a vintage soda fountain.

6-10 PM: Stop in at Tracy Reese’s Hudson Street store and get a free manicure from a Sally Hansen rep.

6-11 PM: Free Essie manicures with diamond-infused polish at Judith Ripka’s Madison Avenue shop, where designer Shoshonnah Gruss will preview her holiday/resort collection. You could win a $500 shopping spree in her showroom or a Ripka ring.

6-11 PM: Sweet deals all night at Rebecca Taylor’s Mott Street boutique, where there’s free cotton candy, a candy bar and $100 off every $350 spent.

PEOPLE YOU MIGHT WANT TO SEE

5-5:45 PM: Vogue editor ANNA WINTOUR will make a rare personal appearance at Macy’s Queens Center along with Michael Kors. The dynamic duo will sign FNO T-shirts for the first 50 customers

6 PM: Fashion stylist and all-around funny guy CARSON KRESSLEY of “Queer Eye for the Straight Guy” and “How To Look Good Naked” will dole out fashion tips at New York & Company’s Lexington and 58th Street store, where there will be food, goody bags and discounts.

6:30-11 PM: At Juicy Couture’s Fifth Avenue flagship store, Vogue editor at large HAMISH BOWLES will belt out Noel Coward songs as waiters on skateboards serve Champagne and nibbles.

7-9 PM: It’s hunk time on the second floor of Lord & Taylor, where the hotties of the 2010 FDNY CALENDAR will autograph a calendar with any $50 purchase.

8 PM: “Real Housewives of New York City” star JILL ZARIN will host a shoe shopping party at Macy’s Herald Square.

7-11 PM: ERIC DAMON, the super hot costume designer of the hit TV show “Gossip Girl,” will be at Henri Bendel styling an accessories shoot.

SWEEPSTAKES

You can enter one time only at each store you go to – so if you go to all 700 participants, well, that’s 700 entries. There are about 70 prizes, some pretty great, including:

* A Carolina Herrera wedding gown and veil with a personal fitting

* $1,000 shopping spree at Topshop with a Vogue editor

* Tix to top fashion shows including Michael Kors, Narcisco Rodriguez, Diane von Furstenberg and Jason Wu

* A Marchesa gown and two tickets to the NYC premiere of “Nine”

* Dinner at Phillipe with Knicks’ forward Al Harrington

At the Americana

The Americana Manhasset shopping center is getting into the Fashion Week act on Long Island, beginning with a kickoff Champagne reception called “Style On the Go” tomorrow from 6 to 8 p.m.

Meet under the tents at Estee Lauder, where more than 20 of the Americana’s fashion experts will gather and give personal style consultations. Sip Champagne, nibble on hors d’oeuvres and receive a complimentary five-minute makeover. It’s all free, but you need reservations, 516-869-2130.

For the rest of the week, there’s loads of informal modeling, fashion previews (Louis Vuitton will showcase its fall runway collection, Burberry will have its fabulous Prorsum line), luncheons and special promotions. For more information, call 516-627-2277 or check out americanamanhasset.com.