SoundSource is for OS X enabling you to switch your audio input and outputs.
New in 2.0 - Volume sliders for all devices, right in SoundSource! (Mac OS X 10.5 only)
SoundSource is a tiny tool for OS X enabling you to switch your audio input and output sources with a single click, and even adjust their volume settings.
OSes: Mac OS X 10.4.0 - 10.5.2
Architecture: PowerPC, Intel
http://rogueamoeba.com/freebies/