Unless your current iBook has PC100 RAM, you'll have to get new RAM as SupahCoolX says. As for the drive, I'd say it's possible. The drive is made from a stock part, some folks were debating about the DVD-R drive taht would be compatible. It would take a bit of work, and unless you have a bit of technical know-how, it might be best left to someone with some experience. It would be a shame to have a broken drive and/or iBook.
I have no first hand knowledge of this taking place so...your mileage may vary.