As AVSM said, use Ctrl + PrtScn to take the picture. Using MS Paint, click 'Image', then 'Paste Image' (I think that's what it says). This will put the image on the screen, where you can save it as a .jpeg. Photobucket will then upload the image for you.
I personally use PaintShop Pro 7.
http://www.subsim.com/radioroom/showthread.php?t=148990