I came across an iBook G4 listed on Craigslist in my city (finally, something Apple related that isn't more than 50 miles away!) the other day, and I emailed them asking for specs, since the ad was not very detailed. I got a reply saying that the iBook was still available and that she wasn't sure on the specs and how to check them, because it was her husband's old computer and she wasn't too tech savvy. I replied and told her to check the "About This Mac" and send that to me, so we'll see maybe.
My question for you more knowledgable on the matter than me is this: From the looks of the photo, it appears to be a 12 inch model iBook G4 in pretty good shape. Is the $40 it's listed at too much, a steal, or just right? Obviously I can try to haggle the price a bit, but I was curious if $40 is way too much for this.
Thanks in advance! 
~Slix
Thanks for the replies guys! 
PPC Macs aren't uncommon around me, it's just that they aren't often on Craigslist for whatever reason. 
Here's the link for those wondering. Doesn't give much info, like I said, but there's a photo. http://racine.craigslist.org/sys/5285256143.html
I'll definitely post back when I hear back about the RAM and processor speed.
And in case you guys were wondering too, I actually have an Indigo Clamshell and a 700 MHz iBook G3 already, but I just like PPC stuff. 
I've been searching for a PowerBook G4 to maybe use as a daily internet/word processing/game computer as an alternative to my MacBook Air, just for fun, but an iBook would fit that role too, so that's another reason I'm interested in this one. They're one of the earliest Apple laptops that still have batteries being made for them from OWC, too.
If you owe a G3 you know much about iBooks.
The G4 doesn't come with a smelly keyboard.

The processor might range from 800MHz - 1.0 GHz - 1.2Ghz - 1.33 GHz
Presumably the RAM is not maxed out at that certain unit.
Certainly you must get a new battery (25$) because the unit one's is EOL.
Below 1.0MHz Leopard is really slow.
In your situation with a 700MHz-G3 I would only go for a 1.2 or 1.33 GHz Model to run Leopard since with your G3/700MHz you have a good Tiger-machine anyway.
Upgrading the Harddrive to a mSata with mSata-IDE-Connector will speed up the iBook significantly.
40$ is a good price for all models anyway, as long as the AC-adapter is included and everything works fine. You could even replace your G3-Tiger, if the G4 is at the low end.
If it's a G4-1.2 or G4-1.33 model in a good shape and good working it's a no-brainer!!!
Add 25$ for a battery, 30$ for 1GB RAM and maybe 50$ for the mSata-SSD-Mod and you'll have a brilliant machine running Leopard, Office 2004/2008, (slow) LibreOffice and a decent version of iTunes and Safari.
I use two 1.2MHz iBooks for Beamer-Sessions: one connected to the beamer providing it's own HotSpot - the second to control the beamer-iBook via ScreenSharing. No fear about USB-virus-infections if anyone brings his USB-stick for presentations.
Hope this will help your dicision.