Looks like TMO has resolved the outage. http://forums.t-mobile.com/t5/T-Mobile-General/Resolved-Intermittent-Service-Disruptions/td-p/325537
..
Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_2 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7D11 Safari/528.16