iPhone now comes the simple step which is built-in to iPhone software version 2.x and doesn't require an additional application to do screenshots. Here's the steps:
- Navigate to the application, web page, or iPhone app you'd like the screen grab from so it presents the image you'd like to see captured.
- Then simply press and hold the "Home" button at center bottom of the iPhone, then press and release the "Sleep" button on top right of the iPhone. This causes the iPhone to "flash" white briefly and the image is added to your "camera roll" on the phone.