Hey guys,
I know the whole free music thing is controversial, but I recently found a cool jazz/jazz-fusion website that has concerts from the 60s to the 80s for free streaming and download and it has some really cool stuff i.e Larry Coryell jamming in a studio with Miles Davis, The Head Hunters with Jaco sitting in on bass and other various concerts. The quality is for the most part surprisingly good. For the record none of the concerts, that I have seen on there, are commercially available.
www.jazzfusion.tv