Simulate an AirPort Base Station. Apple has not included the Airport Base Station functionality in OS X, but there are at least a couple ways to do it yourself using the UNIX side of OS X. Here[base ']s a good article on the process:
http://homepage.mac.com/gdif/masqfirewall.html ; 10:31:23 AM    

How to run a PowerBook while closed. Apple's KBase has a document today offering tips for those who want to run their PowerBooks under OS X 10.1.5 with an external keyboard and monitor attached and the PowerBook closed. [Mac Net Journal]  9:53:43 AM