Okay, I have a 12" PB w/ airport built in and I seem to have some trouble getting on networks from time to time. Basically at school they use MAC filtering and only one of the wireless networks will let me on without any trouble (while the other hotspots occasionally let me on). I have a Belkin wireless router at my house and another at my girl's house...on both I am using 128bit hex encryption and MAC address filtering. Sometime my powerbook will ask me to enter the password and sometimes it will not. Lastly though for some reason I have no problem "seeing" other surrounding networks that...if I choose, I can hop on the unprotected ones with no problem. I guess I would think the problem is with the Belkin routers, but then there is the problem at school...also, my girl's iBook has no problem being "remembered" and getting on the Belkin networks...anyhow, any wireless tips of input would be appreciated!