Technical

The Apple iPhone supports the following audio formats:
AAC (16 to 320 Kbps)
AIFF
AAC Protected (MP4 from iTunes Store)
MP3 (16 to 320 Kbps)
MP3 VBR
Audible (formats 2-4)
Apple Lossless
WAV

Unfortunately, Ogg Vorbis didn't make the list.

UPDATE: Yes, as of the release of iPhone OS 3.0, the iPhone now supports A2DP.

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.

Up until this point there's been little reason to believe that the iPhone would support Cingular's network. Why Apple and Cingular would release a next generation device that was a generation behind in wireless connectivity has left some people scratching their heads. Recently, rumors have started circulating that the iPhone may surprise us again. The New York Times recently reported:

There's been a lot of hype regarding the iPhone. These technical specifications should help settle how the iPhone stacks up to the competition.