Sorry of this is a dumb question, but I haven't seen it addressed anywhere specifically.  Is it possible to connect a MAC Powerbook notebook (or any MAc I guess) to a PC based wireless LAN for the purposes of transferring files back and forth from his hd and mine?  I have two windows desktops and a windows notebook connected with a wireless connection but my friend uses a MAC notebook and comes over my place to work frequently. Just wondering if there was a wireless card he could buy that would work and/or some software is this simply impossible?