Yeah jeromaet, true. Jaguar (10.2) was tcsh but panther is bash.
Yahoo group looks cool, but also try macosx.com (great discussion site) and apple discussion (on apple site under support) if you have questions.
I've got the older 12" powerbook (867mhz) and i really like it. If you go for the ibook you'll want to get as much RAM as possible (640mb like i have). Problem with this is that in the machine you get 2x128mb and you have to throw one away to upgrade! You can avoid this, though, by getting the machine off the applestore website which allows free customization, so you save money. Also, i would HIGHLY recommend upgrading the hard drive to at least 40gb (is only £20 extra, prob same in $). I only have 40gb, and its almost full (half music half program and documents), and its harder to upgrade laptop hard drives later.
On the ibook, you only get vga/svideo/composite outs, no digital outs, so you can't use the newer flatscreens. You don't get bluetooth either, but on the other hand, no portable is going to last that long, and wont keep up with games/video programs for very long, so why spend the extra on the powerbook. I got mine while the ibook was still G3, so it was a different decision.
Personally, i think you get a slightly better product all round with the powerbook because they always pay more attention to building the 'pro' rather than 'consumer' machines.

Last, and most important: The powerbook is a Rev B machine (2nd version of that model) while the ibook is Rev A (first ever G4 powerbook), and the Rev A machines nearly always have bugs. My powerbook is Rev A (867 not 1Ghz), and has well known heat and warping problems that are not present with the Rev B machine (my mum has one). I've had other Rev A machines before (original iMac, original G4 tower) and they've been the same. I'd be worried about the same happening with the new ibook, those portable G4 chips run very hot, and that plastic case is more insulating than my aluminum one.

Goodl luck choosing and have fun with whatever mac you get. Come visit on macosx.com.

ora