I have a PowerBook and all it says on the back is it is a 400MHz. I
just installed Ubuntu 8.04.1 LTS but the display is stuck in 800x600.
Anyone know how to enable the driver to get it up to a higher
resolution?

This doesn't answer your question but ...

I had this same problem with 8.04 on both of my computers, I went to 8.10 and
both monitors are now working in their native resolutions.

Please tell me, it was a PowerPC version ? Macs are something very new in
Romania, especially in Cluj, where some Macbooks can be bought only at their
vendors at Iulius Mall.

It sounds like the video card has not been detected properly. There should
be an fcc number on the back try doing a search for that, it may give you
some more information. The other thing you can try is either manually editing
the xorg.conf found in /etc/X11/ or running sudo dpkg-reconfigure
xserver-xorg and see if you can tweak it up a bit.

try to update first and run 'sudo dpkg-reconfigure xserver-xorg -phigh' and lets
see what happen. basically this will reconfigure xorg.