First of all, welcome!

Next, you might want to check out [link|http://www.thepowerbookguy.com|The PowerBook Guy] for reconditioned iBooks and PowerBooks. I've dealt with him in the past and have had good luck.

The online Apple store does have a [link|http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/71802/wo/Kr6jkGHI3Ky62DepgcX1CNXMMyK/0.0.7.1.0.6.13.0.4.0.0.0.0.3.1.1.0?100,66|Special Deals] page where they offer reconditioned hardware so you may want to check that out. If you're affilliated with a school, you could also look at their education discounts. (About 10% on hardware, I think.)

I don't live with Windows at home myself, but my workplace is quite Windows-centric and I have no problem using my PowerBook (with OS X 10.3.x) there. YMMV, as always.