In most cases, your desktop extends across both screens. You just move your mouse to the edge of one screen and it apepars on the other. It sounds a little silly, but it's really, really worth it. People who use Photoshop and other graphics design stuff swear by it, and it's also handy for programs that you want constantly running, but aren't actively looking at (email client/im/winamp programs.); of course, it's also useful for "real" work--you can pull up information on the web or some reference software on one screen, and write a paper/document in Word on the other, or you can read an article on one screen and take notes on the other. (oh, and welcome to the forums 🙂)