Electronista cites an anonymous source saying that AT&T will begin offering the iPhone to business accounts on January 21st. Among the details includes the continuity of corporate discounts and the requirement of having a data plan at or above $25/month. There will also reportedly be no equipment discounts, and users will be required to pre-activate via iTunes.
Just yesterday there was news that IBM is introducing iPhone compatibility for Lotus Notes users, which IBM counts as approximately 135 million.