Buffy the Vampire Slayer (8 p.m., UPN) begins its new season on its new network with a two-hour episode. Willow and Tara have moved into the Summers' house and are taking care of Dawn; Xander and Anya have a secret; Willow has retooled the Buffybot to masquerade as the Slayer; Giles is feeling guilty and useless; Spike is overprotective of "Little Bit"; Willow is planning a dangerous resurrection spell and Buffy is rotting in her grave. And that's just the first hour. On Undeclared (8:30 p.m., Fox), Steven thinks he's got something going with Lizzie, but she has a boyfriend (in case she hasn't mentioned this enough). What About Joan (8:30 p.m., ABC) opens its new season with a flashback to Joan's first meeting with Jake. On Frasier (9 p.m., NBC), Daphne is jealous over the attention Niles shows a charming patient (Sherilyn Fenn). Jason Alexander plays a neurotic motivational speaker in the laughless new sitcom Bob Patterson (9 p.m., ABC). Is there life after "Seinfeld"? Not for George Costanza, there isn't. The new comedy-drama Scrubs (9:30 p.m., NBC), about interns in a big-city hospital, premieres. Zach Braff and Sarah Chalke ("Roseanne") head the cast.
Come Together: A Night for John Lennon's Words and Music (8 p.m., TNT, WB) features Alanis Morissette, Dave Matthews Band, Moby, Lou Reed, Nelly Furtado and others performing Lennon's songs in a benefit for New York City disaster relief organizations. Yoko Ono executive produced; Kevin Spacey hosts.
Phillies at Braves (7:30 p.m., TBS)
Rosie O'Donnell (syndicated) John Cusack, Björk
David Letterman (CBS) Salma Hayek, Chris Kattan
Jay Leno (NBC) Drew Carey, Maria Bartiromo
Politically Incorrect (ABC) Joe Lockhart, Clive Barker
Conan O'Brien (NBC) Ethan Hawke, Nick Lowe
All times Eastern unless noted.