A 3G version was announced during the keynote. A time frame for its release was not. If you haven't had a chance to watch the keynote, I recommend you visit Apple's site and watch it. IMO, it is well worth the time.
What makes you think that Apple is making $300 on each iPhone? If you are referring to
iSuppli's Analysis, take it with a huge grain of salt. You have to keep in mind that they are
guessing on what components are in the iPhone. Even if they are right as far as the component cost, that does not take into consideration the money spent on R&D. According to Apple, it took over two and a half years to develop the iPhone. That cost has to be included in the price of the iPhone. There are other factors which add to the cost as well. Just be aware that the component cost is only one piece of the puzzle.
Basically what I am saying is I doubt that the future release of a 3G version or the component cost will cause Apple to release the iPhone at a lower price point than they have announced. The may do it for other reasons though. We can only wait and hope

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considering that it has already been confirmed that they are making an iPhone with 3G capability, do you think this iPhone at launch will be a lower price in June, or they will launch at announced price and lower the price of the iPhone without 3G, either way with a profit of $300 on each and a 3G enabled version, a price drop is inevitable.