I am starting to put together some backing tracks that you can use to practice with. They are mostly blues backing tracks. I only have a few so far, but I am working creating more. Some of these I did not create myself. If you use one of these backing tracks and record something with it, let me know - it would be fun for me to hear you play over them! For commercial use, you must get my written permission for the songs I wrote.
I recorded some of these tracks with Cubase SX2, using my Vox AD50VT and my Squier '51 or Squier Tele. Nowadays, I use GarageBand and Ez Drummer for my recording. Some compression and delay were added after recording.
The Lead Guitar Resource - Jam to over 100 Top Rock Bands with Professional Guitar Backing Tracks
Here is a tool I recommend for slowing down music, so you can easier figure out what is being played. It's called Song Surgeon, and it's got some nice features. Check it out.