imitone is a nice application that helps you play any instrument with your voice. This tool translates sound into MIDI, the "language" of digital music. As a virtual keyboard, it can control almost any music app or instrument. Because it is nearly instant, you can sing and feel like you're playing.
imitone also understands humming, whistling, and musical instruments. Optional modes let you control loudness, vibrato, and other effects live.
