There I was, merilly hacking away the apple USB CDC example to try and get my smartphone working on os x.
I then had the bright idea of installing the USB developer extension so I could log the data. After a bit of fiddling I then decided to restore the original extension back and on next reboot the powerbook informed me that the extension wasn't valid and that it wasn't loaded. Eek.
Of course, the keyboard & mouse on the powerbook are USB devices so I had a major problem!
What's really amazing is that I reinstalled off of the dvd and did the "keep user stuff" option. Came back an hour or so later and everything (barring a few system updates) was back up and running, wifi & MSN had even logged in.
Well impressed.
Suffice to say I think I'll be doing my driver debugging on my desktop mac from now on!