AT&T is preparing to offer the iPhone 3G on a no-commit basis beginning March 26, according to a new report. Based on AT&T training slides published by the Boy Genius Report, the no-commitment-required handsets will be available only to current customers, and will be priced at $599 for the 8GB model and $699 for 16GB units. The no-commit option will be offered alongside the current fully-subsidized and early-upgrade pricing levels.

Update: AT&T has confirmed plans to sell no-contract iPhones at the $599 and $699 price points.