This is rather a small concern with the iPhone, but it baffles me as to why it exists: unlike your iPod, you will not be able to use regular headphones on the iPhone, at least this model. It only takes the tiny earbuds that come with it, so far as I know. It won’t even work with the earbuds that come with an iPod.
Hopefully Apple, or somebody, will release regular headphones that fit in the iPhone’s headset jack. Where’s there’s a demand, the market steps in and fills it.