I have the same problem, but it doesnt effect all of the net. For example last night I could not connect to google but could get into gmail! I thought it was probably a DNS thing and after about half and hour it went away and I could get onto google again. No idea what caused it, I was too tired to play about with pinging things or doing any other investigation. Disconnecting from the net and reconnecting did nothing, show it wasnt my connection at least. Seems it was a more major ISP type problem