If your on Vista its built in Just get your image on the desktop and press PRTSC SYSRQ (its next to PAUSE BREAK on the top row of the keyboard) once to have pressed this it copies what appears on the screen to the clipboard. Open up Microsoft Paint, or any other picture or drawing programme and paste. Your saved picture can then be saved to J PEG. Other than that a free one I used until that is MW Snap3 Google it and you can download it free, I think.
Vista? Its been built in since Windows 3.1.</p> If you press alt and print screen at the same time, it only copies the current window. Can save a bit of cropping if thats all you want. </p>