If you are looking for a used MacBook, I posted one for sale on eBay last night.
Check the listing for details, but its 2 year 10 month old with AppleCare until Feb 2010 in excellent condition. My wife used it mostly for Web browsing and spreadsheet crunching, with the occasional viewing of Twilight.
Update
Took 2 tries and one deadbeat buyer, but the laptop was finally sold.