Do you know about the program Band-in-a-box?
Do you know you can get jazz standards for Band-in-a-box free on the internet?
Search for "The Real Book 639k" on this page:
http://www.nortonmusic.com/fake9.html
A good page for biab:
http://www.alisdair.com/gearsoftware/biablinks.html
Or you could buy this:
http://www.nortonmusic.com/fake9.html
And then buy the book that those files are made from.
Do you know about Abersold play along CDs:
http://aebersold.com/Merchant2/merch...ry_Code=AEBPLA
I have used a looper for practicing to short chord progressions, but I would not recommend it for working with long jazz standards when the above tools are available. Biab is great. You can change the tempo, change the chords, play different sections, and you can have it so that it plays through the song with the melody and then without the melody so you can play the melody through the first time and then solo the next time. You can turn the bass part on or off, and you can have different instruments playing the melody.
In fact, I should be doing that right now, what am I doing sitting here again when I should be practicing. I was only going to pop in for a moment and here I am writing this long message...