There has been a fair amount of work done in getting Linux to run as a true AccessPoint but so far there hasn't been too much visible work on getting the BSD's to do the same. Here I document the projects that I am aware of. -- AdamShand
See also: LinuxAccessPoint, HostApMode
Hack to install BSD on an Apple AirPort.
Configuring a FreeBSD Access Point for your Wireless Network (from SysAdmin Magazine - samag.com)
-- Posted by DaillestProphetic
Actually, it looks like it's a hack now to install linux on an apple airport. --ForrestEnglish
Preliminary HostApMode drivers for BSD