USB Preamp?

I have a general electronics question for the gurus here, and I'm really not sure if Arduino is related or not, so my apologies in advance if the answer is "no".

I'd like to build my own USB preamp, similar to (but simpler than) this product: http://www.m-audio.com/products/en_us/MobilePreUSB.html

I'm just curious about what would be involved as a fun project. Ideally I'd be able to plug in a 1/4" jack and have some kind of gain knob and clipping feedback LED. Anyone have any thoughts on this? Is it possible? Is it crazy?

Adam

look into the lm386 from radiocrap...i mean shack. pretty easy to set up, i think you only need about 4 parts to get it going. as for clip detection, im not sure, but the TDA amplifier chips tend to have an output for clipping detection, check out some of their datasheets.

Great! Thanks for that.

Do you happen to know anything about the actual interfacing with the computer? Does anyone have any idea how to get Mac OS to recognize the USB device as an audio-input device? I wouldn't expect to need special drivers, since most microphones don't require them; Core Audio just somehow knows how to use them.

Apologies for my ignorance. Any more thoughts?