Max/MSP External for Beat Tracking based on Adam Stark's BTrack
Mac OS X Only
Looking for Windows/Pure Data version?
Take a look at IBT object by João Lobato Oliveira et al!
http://smc.inesctec.pt/technologies/ibt/