Take Pictures With Your iPhone’s Headset Using iOS 5
In the new IOS five there will be the ability to use to volume up button on your Apple device to take a picture. In much the same way you can use the volume up button on the actual handset, it seems, that you can do exactly the same using your in-line headsets as well.
Of course you will need a pair of earbuds or third-party headphones that support Apple's volume up and volume down functionality to get this to work (but whatever you do don't get these LINK)
This feature is going to make those e-mail holding a camera at arms length shots become even more commonplace but I suppose it will take steadier shots as you can place your iPhone on a stable surface and snap away.