That's great, but there are a few things about the PowerBook that prevent an iBook from approaching it as a computer, even when you upgrade the optical drive, RAM, hard drive, and so on.
I would also pay someone else to crack open the case of an iBook, over doing it myself, any day, although I've installed drives and RAM and cards many times.
www.pbfixit.com is another good source. See:
http://www.pbfixit.com/Guide/83.0.0.html