For the love of everything kind, please include the Airport Card.
I don't know about other eBay iBook shoppers, but I immediately disregarded any iBook that didn't have an Airport (Extreme or not) Card installed, unless the price was decent. Many people think they can "milk it for all it's got" but you'll get more bids if you include it. In the end, I ended up purchasing a G4/800MHz/40GB/512MB RAM iBook without the AE Card because it was such a great price ($475).