Almost.Â There will be new headphones which are similar to those of current iPods [1/29/07], but which incorporate a microphone. Calls can be answered and ended by squeezing the microphone. Wireless earpieces that use Bluetooth technology to communicate with the iPhone will be sold separately.
Probably. An industry analysis firm named iSuppli recently performed a teardown analysis on BoM (bill of materials) costs involved with the iPhone, added estimates on royalties and other costs Apple will incur, and have estimated that that iPhone will cost Apple roughly $280 to make. At that price, there's plenty of room for Apple to make $200-$300 profit on each unit they sell.
UPDATE: Yes, as of the release of iPhone OS 3.0, the iPhone now supports A2DP.
The "high technology" sensors (as Apple calls them) in the iPhone are some of the more exciting features this new device brings to the table. These sensors won't result in the iPhone doing anything other phones aren't capable of, but it will let the iPhone do it without instruction from you.
The proximity sensor:
Yes, the iPhone will work overseas, and not just in Europe and Asia. The iPhone is a GSM (Global System for Mobile communication) phone. GSM, which uses narrowband TDMA, was first introduced as a standard in 1991 and is now in place in over 100 countries.
Access to receive and place calls from outside the United States will require additional services from AT&T/Cingular, which you will need to arrange with them before your phone will operate in such a fashion, but the phone is perfectly capable for worldwide use.