Was helping a friend with his Early '08 MBP. He was having wifi issues associated with Lion. This is what we did in the order we did it, he has not had any issues in 5 days at this point. trashed /Library/Preferences/Systemconfiguration folder Reboot Do not join a wifi network open system preferences go to network go to wifi click advanced remove all preferred networks in the list if there happen to be any there. click ok click gear icon at bottom of network sources pane click set service order drag wifi to top drag Bluetooth DUN/PAN both to bottom Click ok. Reboot Join a network. I hope this helps someone, it worked flawlessly for us.