the last of the old-style 'Clamshell' iBooks had a FireWire port and was capable of importing video etc, etc - with only 466MHz and a 66MHz system bus.
I've never tried doing any on my iBook (white, 500MHz) but it too is said to be capable. So, for video stuff, you don't need the latest and greatest and fastest, but at a guess doing video on a machine like mine would get annoying after a time. I know mine does alright with still images though (importing from digital camera, etc.) Apple software for both still photo and video work seems to be very highly regarded.
Hope this helps, even if only very slightly!