If you want a good play along music program that is excellent for practicing, mTrax can slow down the tempo to your pace especially if you don't want the extra hardware of a TASCOM or other similiar device. Try mTrax for your practice sessions. You will not be disappointed - the cost is $50 but they offer a 14 day free trial before you purchase.
mTrax is a software program put out by the Terra Softa company which enables you to load music files from your computer into mTrax "libraries". You can control the speed (tempo) of the music and also the pitch (key)- it does a lot more, but I have not got around to investigating all the details.
So if you are having problems getting players together for practice sessions or afraid of boring other players with you slow leads, mTrax will give you your own personal back up band that plays at your tempo. Also you can slow down small portions of music to riffs and fill ins used in the song you are practicing.
If you are interested, search the internet using mTrax - but don't confuse it with stock tracking programs! You won't be dissappointed!