audio in?

hi!

I'm building a VU meter and would like to know how I could tap into an audio signal (coming from iPod or PC) using the Arduino. Can I just attach it to an analog in pin? How could I do some frequency analysis on the Arduino to make it react to the beats, etc.? Any tutorials on that? The Arduino will not have access to a PC so all needs to be computed on the chip itself. Thanks!

Although it is not exactly your application see:- http://interface.khm.de/index.php/labor/experimente/arduino-realtime-audio-processing/

For the audio input interface and also some examples of things to do with the readings.