www.furthurnet.com
Best site i have EVER found for live music and bootlegs. There are TONS and TONS of bands on there...lotsa "jam" bands like the greatful dead, there are also hard rockers like AC/DC and Metallica on there.
If you have ever been to a concert and want a copy of the chow to listen to over and over again, check this place out...you may be surprised what you find!