Etymotic, whose high-end headsets have become iPod sound weenie status symbols, now has a pair for the iPhone. The hf2 is similar to the ER-4 headphones, with the addition of microphone. They're avaiable now for $180.
BTW, did you know that "canalphones" like the Etys, which improve sound and screen out extraneous noise by sealing tightly in the ear canal, raise the temperature inside the ear canal just enough to maintain a perfect environment for liquid ear wax? Which means you really don't want to be promiscous in sharing these puppies, and it's worth thinking about the cleaning and "yeew!" factors before you buy. Unless you're French, in which case they'll just be a reminder to buy cheese.
Etymotic hf2 headset for the iPhone [TUAW]
