It turns out there's a reason behind the iPhone 3G's dramatic price cut ($199 for the 8GB model)--AT&T has agreed to subsidize the phone in return for a $10 increase in monthly unlimited data plans. Unlimited 3G data plans for business users will cost $45 a month in addition to a voice plan, presumably because of a higher consumption of data. So even though the phone itself is cheaper, it will cost you more in the long run. That said, the faster 3G data service might be well worth it to most people.
This new revenue-sharing plan is a departure from Apple's previous deal with AT&T, where AT&T gave a portion of the monthly usage fees to Apple. Now Apple is in a much more traditional deal with AT&T, where the carrier subsidizes the phone upfront in hopes of earning back the cost of the phone over time.
Also, there's news that if you bought the old iPhone after May 27, you can return it to the store to get a new one without incurring an additional handset charge (though you still may have to pay the restocking fee). We have yet to confirm this, though; we'll keep you updated as soon as we contact our sources.