where does the sound of a USB microphone go?

I have a Philips USB webcam with microphone. When I plug it into my computer it is recognised. Video is registered as /dev/video0. It also says "registered new driver usb-snd-audio". But where does the audio go? There is no mention of an associated device. I can see the microphone in KMIX, but only as an input! There is no output associated with the mic. If I do "cat /dev/dsp > test", the file stays empty.

How can I get sound from my mic?

I don't have a microphone in this test.
I've just tried 'cat /usr/share/games/imaze/sounds/kill.au > /dev/audio&' and it works properly in my knoppix 3.8.2 HDinstall.
I guess you can record something with 'rec test.au' and then 'cat test.au > /dev/audio&'.