It's a GUI for Fink - the utility that lets you install Linux stuff on OS X. It wasn't that intuitive when I tried playing with it a year or so ago, but it'll give you a feeling for what should be easily installable from GNUland.

[link|http://finkcommander.sourceforge.net/|Fink Commander].

You might also want to install the touchpad expander thing that [link|http://z.iwethey.org/forums/render/content/show?contentid=201139|Spiceware ] has posted about in the last few months. Out of the box (at least on our 667 MHz 15" TiBook) the touchpad just moves the pointer - you have to hit the button to click. (I haven't tried it on ours yet.)

Also, check to see how long it lasts on the battery in case you want to order some spares when/if you get one of your own.

HTH. Have fun with it. Powerbooks are very very nice laptops.

Cheers,
Scott.