Chord sequencing program for improv?

i need a simple chord sequencing program for jazz improv practice because aebersold is WORTHLESS. They arrange their own versions of standards so they can get arrangement copyright and then you go to play the real version and all the chords are different! I don't want to buy a thousand cd's, I just want a simple chord programmer so I can practice the real versions of these songs. Any suggestions? Freeware would be really kickas s s s s s s s s s s s s s s s s s