Currently Being ModeratedJun 5, 2011 8:52 AM (in response to ricoiphone)
Does this happen on both WiFi and cellular data, or only on one (or the other)? I ask because it sounds like a DNS error, but that would only happen on WiFi if your router has an incorrect setting.
If it happens on both cellular and WiFi go to Settings/General/Reset and Reset Network Settings. You will have to re-enter WiFi passcodes, but nothing else will be lost.