My father's internet connection no longer works after the update. He can access his wireless network, print wirelessly and, if the ethernet cable is plugged directly into the PB, can surf the web. He cannot access the internet wirelessly.
I'm 6000 miles away and after 4 days of phone support, he called AppleCare directly. After 4 hours AppleCare left him with a machine that couldn't connect to the internet at all. Luckily I had him backup his old /Library/Preferences/SystemConfiguration folder and could restore him back to at least a wired connection.
I'd love to know if your issues are related - what did you change to get it working again?