Between Walk the Line, Rent, and The Producers, it's a great year for music in movies. But not in the Best Original Song Oscar category. Only The Producers contains material written expressly for the movie: ''There's Nothing Like a Show on Broadway,'' a new Mel Brooks tune that Nathan Lane and Matthew Broderick sing over the closing credits. So what could fill the void? Brokeback Mountain's beautifully spare track ''A Love That Will Never Grow Old,'' co-written by Elton John's longtime lyricist, Bernie Taupin, and sung by Emmylou Harris, leads the contenders, while Chicken Little and Tim Burton's Corpse Bridefeature new songs by Barenaked Ladies and Danny Elfman, respectively. Oscar winner Bob Dylan (Wonder Boys) has ''Tell Ol' Bill'' in North Country, and nominee Dolly Parton (''9 to 5'') did ''Travelin' Thru'' for Transamerica. The most twisted potential nominee? Sarah Silverman's nursing-home rant, ''You're Gonna Die Soon,'' from Jesus Is Magic.