How to match tempos of two songs

JCody
I have a finished track and a piano track of the same song. I need to match the tempo changes of the piano track to the finished track. Anyone know how to do that quickly?
 These are audio tracks.

How far off are they, and how often do they occur (e.g., small changes over long times, drastic changes over short times, etc.)? There are several options depending on the answer, and picking the right one could make the difference between "project done, yawn, let's go see a movie" and "Sonar sucks, need to vent in forum." 
 
Also just to confirm - the tempo changes in the piano are the "master" and you want to conform the finished track to the piano, right? Also, are they both stereo tracks?

Split/ctrl stretch is tedious but this kind of processing involves judgement calls, and humans are good at that sort of thing 
 
The only automated process I can think of would be using AudioSnap to create transient markers for the piano, assign them to the pool, add transients markers to the other track, and snap them to the pool. But that would require prep work and might end up not saving much time, if any, in the long run.
 
Just remember to render the stretched tracks to preserve the fidelity...