From what I've heard, the discs that come with a computer have a version of the OS that is made for that computer. So it's not exactly a full version of the OS. For that matter alone, I'd be skeptical. If you're going to try it, better back up first and have your 10.2 disc (or whatever you have for the powerbook) handy in case something goes wrong.
With that in mind, if it's labelled as an iBook disk, it won't actually let you do anything with it in the powerbook. You can boot up with it just fine, but before it installs anything it will do a hardware test and then tell you that the disc isn't compatible with your model of computer. So if you want to load it, you're going to have to figure out how to hack it.