So yeah, I'm looking for anything Jazz because I love to listen to it. I'm a big fan of the Cowboy Bebop, Big O, and Baccano soundtracks. Also, I absolutely love the Bartender soundtrack and Artistic Transformations by Vince DiCola, both of which are very piano heavy. Faster music is better too.

There is a thread like this in the Non-VGM forum here:

Thread 71497

I recommended some stuff there if you want to look.

If you mean original Jazz music used on soundtracks made by non-jazz musicians, i can recomend you The Man with the Golden Arm by Elmer Bernstein, or Naked Lunch by Howard Shore with the colaboration of Ornette Coleman and Thelonious Monk, or The Cooler by Mark Isham.
If you want a more light tone with a 60's swing style, you can found on early John Williams works like Checkmate, How to Steal a Million, Bachelor Flat, Penelope, A Guide for the Married Man. Henry Mancini also done some albums with this style, but i don't know much abiut his work.
Another album worth to mention is Swing Kids by James Horner, which has some Jazz compositions.
Otherwise you can check the thread jakob.nelson posted for you.

Oh awesome, I didn't know about Thelonious Monk working on Naked Lunch. Thanks!

Oh awesome, I didn't know about Thelonious Monk working on Naked Lunch. Thanks!

It's just a little piece actually, with half of a 1:30 cue, but he's credited.

I saw the thread with the tracklist. Yeah, it looks like its just half of one track using "misterioso." I'm getting it anyway, thanks.

Within the Anime & VGM section, there's also this thread (Thread 69509).

I know a good song full of jazzy goodness: <a href=http://www.youtube.com/watch?v=V_tfRVx1hqs> Nightclub from the FPS Timesplitters 2 </a>