Courtesy of one of the nice guys of the startup world Pat Phelan, the above video demonstrates how you can take iPhone screenshots.
The shorter version:
– Open the page you want the shot of
– Hold the home + power buttons for around 3 seconds
– let go, you’ll see a flash, which is the confirmation that the screenshot has been taken
– connect your iPhone to your computer to extract the shot(s). If you’re using a Mac, the screenshots will appear in iPhoto.