a very easy way I was able to create a few progressions to practice soloing over was to do just that... I used the phones line out to the line in on my pc and the sound recorder that comes with windows xp or there are a bunch of good free tools out there that will let you edit and loop your track..
then I use the laptop to play rythm section while I use the line in thru the lt to the phones to control the volume and be able to record again, but this time with the solo on it...

it's cheap and cheezy but know what? it works and I didn't spend any money...