In this podcast, Talksina gives us a demonstration of Audio Switcher, a Mac OS X utility that allows you to quickly switch your audio input/output between different components.
Audio Switcher sits in the Status Bar, making it conveniently accessible from any application. Audio can automatically switch to a given device if selected in the preferences. Place it in your Login Items and it will be available whenever you login. Audio Switcher can auto select any device you choose whenever the device is inserted or if the device is available at launch.
Additional Notes From Talksina:
I forgot to specify it inside the podcast: Audio Switcher can be managed only by mountain lion's voiceover users, as this is the only system which allows voiceover to access the extras menu
Second note: if you have lots of third-party apps starting at login, i suggest you to go to the finder, and access the extras menu from there as you are sure to access them all it happened to me that if i was on iTunes and tried to access audio switcher, i found dropbox, vmware, fullcontrol, skype but not audio switcher... i had to turn some other apps permanently off.