Dual Booting the Powerbook

I use Linux and OS X as my primary operating systems. Lately I have been using the Powerbook exclusively with ssh or FreeNx to work on the Linux machines on the network. I started off to simply repartition my Powerbook and then reinstall OS X and put Ubuntu on the new partition. That was two days ago. Things are pretty much back to normal now. I have a dual boot system that I can take with me and run my favorite GIS software on both platforms as needed.