If you've had any type of headphones plugged into the iPhone when you're on a call—including that tape adapter you have for your car—you'll notice that you can hear the person fine, but they can't hear you. Obviously, that's because there's no microphone on those headphones you're wearing. Shure's Music Phone Adapter let's you use any set of cans as a headset by adding an in-line mic in the adapter. Sure, it's pretty pricey at $49.99, but the privilege of using any set of headphones to make calls could be worth it if you have some expensive $399 Shure headphones you don't want to take off just to make a call. [Shure via MacWorld]
I was using my regular Sony headphones and decided to try to make a call. To my surprise, the person I was calling could hear me as I held the phone somewhat close to my face. I guess the iPhone is smart enough to using the built-in mic when you are using a headphone that does not have an in-line mic.