> for NetBSD, and installing NetBSD into the PowerBook. Also, are there
> other issues I should be aware of before spending the $$$s? 

I didn't succeed to install netbsd on my titanium (gigabit ethernet):
I've got the
'console keyboard type: console'
error when i boot the content of the cd from an HFS partition.
The 1.5.2 macppcISO isn't bootable and the iso i make aren't bootable 
too (it's very difficult to make an apple bootable cdrom).

The list of supported models:
http://www.netbsd.org/Ports/macppc/models.html

Macppc port install notes:
ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-1.5.2/macppc/INSTALL.html

Some links from the macppc FAQ:
http://www.netbsd.org/Ports/macppc/faq.html#pb418
http://www.netbsd.org/Ports/macppc/faq.html#ofw-access
http://www.netbsd.org/Ports/macppc/faq.html#ofw-use

I don't know why but there are a lot of posts about G4 powerbooks here, 
so you will find out that quite a few powerbook G4 users has got 
difficulties to installed netbsd on their machine.

I installed SuSE Linux 7.3 PowerPC Edition and MacOS_10.1.1 but i 
couldn't installed netbsd.
Moreover, i've got hardware problems with the combo DVD-CDRW drive, I'm 
obliged to give it back for the second time now.
Nevertheless, it's a great machine and macosX is an incredible os.