The sense of urgency and got-to-get-there attitude were palpable at the sev enth annual Vanity Fair party celebrating both April's Hollywood issue and that coveted golden statuette. Hollywood's biggest prom night began with a seated dinner at Mortons, with the renowned from a host of industries-from Mr. and Mrs. Walter Cronkite and Mr. and Mrs. Ahmet Ertegun to Mr. and Mrs. S. I. Newhouse Jr. and Mr. and Mrs. Robert Pittman; from Barry Diller and Diane Von Fursten berg to Mr. and Mrs. Charles Gwathmey, and Hollywood's royals Audrey and Billy Wilder. After a record-length, four-hour Oscar show, the dinner crowd was ready to tear down the walls. No need, as VF. punched through the back wall to reveal a dramatically tented room constructed specially for the evening. Awaiting guests were impeccably groomed hedges, plush lounge areas (where Christina Ricci whispered conspiratorially to her sister), cherry-veneer bars (where Jennifer Aniston pined for a margarita), and a centrical couch (where for a while Tony Curtis and Jill Vanden Berg held court) Those who slipped in effortlessly included the new order of Holly. wood's hot (Tom and Nicole, Uma and Ethan, Edward and Salma) and longtime lu minaries and graceful presences (Angie Dickinson, Catherine Deneuve, Betsy Bloom ingdale, and Artie Show). Guests burnished the parquet to the big swing sounds of the Todd Londagin Bond and the DJ. mixings of Grammy nominee Hex Hector. And those golden statuettes? It was Oscar, Oscar everywhere. Hilory Swank brought hers. As did Kevin Spacey, Angelino Jolie, Michael Caine (but left it in the car for safekeeping), Pedro Almodóvar, Rick Heinrich, and-the last arrival just be fore the bar closed and the barricade was shut down-first-time winner American Beauty director Sam Mendes.