For those of you who don't know, Last.fm is a great place to listen to free music and hear new bands.
They've got a 'Glastonbury Radio', which basically plays music from nearly all the bands that are playing there. It will randomly pick songs one after the other to play, so you get to hear a mix of music. If you don't like the song, you can skip it
http://www.last.fm/festival/1626411+...ming+Arts+2011
That is the link for Glastonbury as an event on there, if you scroll down you can listen to the radio. I'm not sure if you need to sign up to their site on not, but it's not a spammy site so nothing to worry about if you have to.
I've heard some really awesome stuff on there, and not just from the Glastonbury Radio