You can (sometimes) get an 802.11b card to act like an access point, but it's also possible to run in Ad-Hoc instead of Infrastructure mode, which allows a network to be built from a collection of clients without an AP. This is not 100% supported, as it's supposed to be a demo or temporary solution, and some cards (drivers, really) don't support it at all. To add to the grief, the nomenclature has become contaminated, and the same term can sometimes mean two opposite things.