Don't know if anyone here knows of this site, but if you go to http://www.archive.org you can find literally thousands of free live shows dating from the 60's up until present day. Most of the bands are jam bands such as Grateful Dead (2995 shows alone), String Cheese Incident, Bela Fleck, Yonder Mountain String Band, Robert Randolph, etc but there is some other stuff on there too. You can find all types of rock from jazz rock to bluegrass and some indie like Guster, Decemberists and Death Cab. Check it out if you are into live jam music, I highly recommend it.

Archive.org rocks, I used it a few months ago to look up some live shows from one of my favorite bands, Rustic Overtones, who broke up. If you're into any smaller independent bands, I highly reccomend it.