To enable screenshots:
1. Open your "swkotor.ini" file located in the game's root directory "SWKotOR".
2 under [Game Options] change the 0 for a 1 in the EnableScreenShot line so you end up with this:
EnableScreenShot=1
Save your file and make sure it has the ".ini" extension and not ".txt".
You can hit the print screen key (normally a key located near the top right corner of your keyboard - on an English Keyboard it says "Prt Scr" sometimes but this may vary with the keyboard manufacturer)
Pasting your image in Paint will do.
Personally, when I take a series of screenshots, I like to use Reclip:
http://lockettefamily.com/reclip.htm)