Here you can find my latest product :-) METRONOME FOR CELL PHONES. Enjoy and support it if you can.
What you need is: Cell phone with JAVA support (J2ME/CLCD1.1/MIDP2.0) - almost every cell phone has it!
This app is optimized for 240x320 resolution but it should also look well on other displays like e.g. 176×220. I've tested it on Nokia 6300, Nokia 6650d (Symbian), SE k750i, SE w580i, SE c702, SE k550i and it works fine. I've also made some precision tests by recording this app on microphone and calculating the tempo on the waveform and it's 100% precise - as well as every other metronome on BestMetronome.com! If you can't hear any sound but app is working, try to change your phone profile to loud one or turn on all sounds - alert sounds, game sounds and so on.