Mobile Metronome

Developer: Gabriel Simões
Price: Free
Mobile Metronome can take care of all your tempo needs.  Not only is it accurate, but it is also easier to use than a physical matronome.  You can choose any tempo between 30 and 230 bpms, or you can tap in your own beat and it will tell you the tempo, which is a lot of fun.  Additionally, you can choose a time signature as well as the beat subdivision.  You can also choose among 4 different sounds to pace yourself.  If you need a metronome to play an instrument, this is the app for you.