Customers in the Midwest and the Southeast regions "may be experiencing trouble accessing data on some devices" said a spokesman for AT&T. Not all of them, but the iPhone is included in the list. Voice calling is not affected. The issue began this morning at approximately 6:30AM EDT, and technicians are working to identify the cause and resolve it as quickly as possible. However, an insider who works on networks dropped me a line as to why AT&T's 3G network is having these sporadic issues today: apparentely, six GGSNs "rolled over". (GGSNs are gateways between wireless and regular networks, and when they roll over, they switch from GGSN to another.) UPDATE (1:49): AT&T said service should be fixed by now.