I found a nice little Java-based toolkit called "Allegro" consisting of beat counter, metronome and tuner.
Right now, it works only with Siemens S55, M55 and SL55, but it will be available for other Java-mobile phones in the near future.

Details and (free) Download at:

http://www.dimjon.de/
--> midlets --> allegro

Check it out ! [img]smile.gif[/img]