AT&T is offering its remaining stock of 16GB iPhone 3G units for $149 with a two-year agreement, according to the Boy Genius Report, a popular Apple/tech blog.

Citing an AT&T insider, the report speculates that since Apple is only offering the 8GB model via its website, 16GB units may be available on a “while supplies last” basis. Apple didn’t mention the 16GB model during today’s Keynote Address, suggesting that these discounted units are not part of its long-term strategy for the iPhone.

Basically, they’re clearing out stock, a fairly typical corporate strategy given its view that this is “old” technology at this point.

Many expect the existing stock of old model iPhones to be gone within a month or two, with the hype of the new phone and the sell-through prices.