Visual Metronome is a metronome for the iPhone and iPod Touch that provides both audio and visual beat indication.
Visual Metronome has a lot of benefits over other metronomes in the App Store. One of the most important of these is timing; be sure to check out the comparisons page to see how Visual Metronome's timing is superior to other metronomes available. Other advantages include the ability to place accents on any beat of a measure and very clear visual indication of what beat the metronome is currently playing.
Visual Metronome also has a minimal, easy to read interface that is much cleaner than the competition.