Mandrake 9.1 PPC is a pain in the butt to install on older powermacs (grey tower). If the powerbook is the same generation as the early grey tower, it will be a difficult installation including an editing of the mac's boot system. I forget the process because I only tried it once and without success. On newer mac hardware, the ppc version is supposed to be much easier to install.
Also Mandriva (Mandrake) has a new version for install on ppc. That might work better.
http://www1.mandrivalinux.com/en/ftp.php3 << about 1/4 down the page are links to the ppc version of Mandriva 2005. Chances are good that it will install better than older 9.1
