iOS does not natively support access to your computer's hard drive, but there are third-party apps that do provide such capability if you set up file sharing on your computer. FileBrowser is one that is commonly recommended (I have no personal experience with it myself).
http://www.stratospherix.com/products/filebrowser/
Confirm that it can connect to your version of Mac OS X; a very old version may not be supported.
If the iBook won't boot, then you can't access the drive. As Kappy suggested, pull the drive out of the iBook and connect it to another computer to access the data. That will probably be a better option in any case unless all you want to access are a relatively few documents.
Regards.