Fat Wreck Chords has done something very cool, with fatfreeradio.net. Lot's of songs, by lots of bands, and since it's in shoutcast/mp3 format, it actually doesn't sound like shit.
From Fat's news page:
FAT FREE RADIO up and running!
FAT WRECK CHORDS has a radio station! It's located at fatfreeradio.net. It's got tons of songs by FAT WRECK CHORDS bands, but it's also chock full of other old and new school punk bands. GO CHECK IT OUT NOW. This ain't your mommas radio station.