From Fox Mobile Entertainment, Inc.:
Munk yourself with the official Alvin and the Chipmunks: Chipwrecked iPhone application! Change your voice to sound like a Chipmunk, Chipette, or Major Rock Star! Playback and record to share with friends! Save and send ringtones of your Munked voice! ***PLEASE NOTE*** - The iPod Touch 2nd Generation does not have an internal microphone. In order to be able to use the "Munk me!" feature you must use the white Apple ear buds with the microphone in the cable, or other iPhone-compatible external microphones.