Here are some free and legal mp3 downloads of songs that John Peel has featured on his Radio 1 show recently. All these tracks have been made made available by the bands or record labels themselves, they don't involve Napster or anonymous postings to alt.binaries.sounds or anything like that. The idea is that if you like the track, you'll buy some of their records, which seems pretty sound to me.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.