Down, down, down. That what the blogs and the Twitterverse are saying about AT&T’s data network in the northeastern United States this morning.

Reports have filtered in from Philadelphia, New York, and Boston that iPhones are adrift in a data-less existence, with some saying that problems are being experienced as far west as Chicago and St. Louis. Even those phones will full signal strength are seeing zip in terms of data, suggesting that the problem is with AT&T’s network hardware.

After seeing a note about the outage on both Gizmodo and Engadget, I fired up my iPhone here in Boston and found that I couldn’t reach any sites via Safari: after thirty seconds or so of the spinning wheel icon, the connection would basically timeout. Attempts to launch Twitterrific and the App Store or to check my mail were equally unsuccessful.

Disabling 3G Networking didn't seem to have any appreciable effect either. The outage does, however,only seem to affect data, as I was still able to make voice calls normally.

I tried to get in touch with an AT&T spokesperson, but I didn’t get a response by the time I posted this piece. We’ll try to get more information as the situation progresses.

Update 12:52PM ET: The problem seems to be fixed, and service is returning to the affected area, though it does appear to be sluggish in some places (such as here in Boston).