I haven't used MSN Messenger myself, (Cory?) but I will gladly put a copy on my Mac and give it a test ride. I can't see why it wouldn't work !
I would suggest you have a look on the
Apple iSight pages they have some good info there.
iChat working with an iSight is very good !
Have a look here
...oops have just remembered...
iSight 'technically doesn't work with a G3 iBook, (unless it's 600mhz up)
I have however got my iSight to work on my Wife's iBook and her's is a 500mhz one, it needs a piece of software called iGlasses, to trick it !
Hmm you'll have to let us know what 'speed' your iBook is ?
regards
Ric