I was hoping to use GarageBand instead of Audacity as part of my recording suite, but the stars aren't aligned...
The only mic I have on my desktop G4 is my iSight camera, which sounds pretty good, but runs at 48KHz. GarageBand only likes 44.1KHz sources, so it doesn't work.
Doh. Looks like I'll be sticking with Audacity. There wasn't a real reason to switch, just that I like GarageBand a lot ;-)