Getting started with Arduino sound

What's a good website that has some introductory sound generation info/projects/tutorials for messing around with Arduino-generated audio -- no shields, just the Tone library or something similar -- with hardware?

Did you look it the Learning section, or the Playground section?

http://arduino.cc/en/Tutorial/Tone

This is good for real time audio processing:- http://interface.khm.de/index.php/labor/experimente/arduino-realtime-audio-processing/