Gadwin PrintScreen is a very handy freeware application that allows screen capture/screen shots. I particularly like that it will save the captured image (I usually capture a rectangular area but you can choose to capture the entire window or screen) as a JPG, with a small drop shadow/border. PrintScreen puts the image on the clipboard as well as saving to a file, making it perfect for product demos and bug reporting — you can grab multiple images very quickly. There's also a professional version that adds annotation and other features.