Update: Associated Press confirms that the AT&T wireless data network is down in parts of the eastern US. Affected areas include Massachusetts, New York, Rhode Island, Maryland, Pennsylvania, Virginia, Illinois (not part of the east last time I checked) and Missouri (ditto).
Voice service remains unaffected but Web surfing and email are not functional. Surprisingly (not!) most outage reports came from iPhone users, once again proving that the iPhone is the first smart phone that really gets used as an Internet device (versus as an Email-specific device).
Rumors say that AT&T has been hard pressed keeping up with the iPhone demand on the data network -- because with an iPhone it's really easy to get online and surf effectively.
Update 2: TUAW Reader Tim writes that he was given a credit for the outage this morning. If you're seriously put out by the lack of data service, it may be worth a call to AT&T. You may not get the same $25 credit Tim got but you may be prorated for the downtime.
Update 3 South New Jersey seems to be affected as well.
Data still out for you? Share your location here or continue reading for a map.
Update DC Area seems back online. First reports that Boston is back.