www.pandora.com

register for free, then make up "stations" by band. It plays the band you name, plus similar bands. I have Def Leppard, Judas Priest, Thin Lizzy, Led Zep, Pink Floyd, Deep Purple, UFO, Neil Young, Molly Hatchet, hendrix, CSNY, CCR, Scorpions, ZZ, well you get the picture

It plays like every 3-4th song as the band station you selected, mixed with the similar tunes, and you can vote up or down on each song it plays.

Never seen anything like it. I have the Thin Lizzy station on now, and its playing Rock Brigade by Leppard from 1988

oh yeah did i mention, it remembers where you left off when you close the window