Just call it the Janet jitters. Perhaps in response to Ms. Jackson’s Super Bowl striptease, Grammy style was much tamer this year. Which isn’t always a bad thing. Though Justin Timberlake looked more PricewaterhouseCoopers than party boy in his nerdy striped tie, Christina Aguilera’s elegant Versace made us forget her undercleavage at the 2002 VMA’s. Beyonce — who scooped up five awardswas also a big fashion winner in a gorgeous Roberto Cavalli mini for her duet with Prince. She should’ve given some pointers to OutKast, whose emerald ensembles — like those of Queen Latifah and Snoop Doggmade green the new black. Now that’s nasty.