weird wireless problem

I can connect to my neighbor's wireless network through my iMac's airport... but my network which was working wonderfully until yesterday remains active and present but doesnt DO anything! For example I try to go to the iTunes music store and I get a network error, I try to start iChat and nothing happens... not connection can be made, and safari won't load a webpage... and yet it says I have perfect signal... Yes my WEP is correct.

I get this message when I run network diagnostics:

Cannot find server

This computer appears to have a working internet connection, but cannot find "www.apple.com". You may have typed the address incorrectly.

Anyone have any ideas?

Thanks.

long story short, your firewall is on and services like ichat or internet aren't being let through the correct ports, what version of mac os x are you using? and what router are you using?

You might want to try setting your router to broadcast on a different channel.

hey guys i figured it out... it was actually a problem with comcast... the bill got shuffled away and wasn't paid on time... So they suspended my account, I called them and I'm back online.

Thanks for the responses.