According to a Macworld UK article, AT&T chief technology officer John Donovan last week confirmed the US carrier had been "unprepared for the US success of the iPhone 3G."
The information was gathered from statements made by Donovan at the Goldman Sachs Technology Conference last week. Donovan reportedly admitted that demand for 3G services in some areas exceeded expectation, causing AT&T to scramble to build up it's capacity in those areas.
In light of the recent lawsuits filed against the Apple and AT&T these public comments are very interesting indeed. They could help explain common poor 3G reception, poor switching between EDGE and 3G, and frequent dropped calls because the iPhone and/or network is unable to process the handover from 3G to EDGE or visa versa. Complaints continue even after the release of iPhone OS 2.0.2 and 2.1.