Quickie: I discovered recently that my Dell desktop (about 4 months old) had a display adapter with both a digital and analog connector in the back. I suspect most newer computers have that. At any rate, if you are running XP, you can spend $300 on a 15" LCD display and use XP with two screens!
Now most people who see this setup first say: "Why?????" All you have to do is remind them of what it's like to be looking at help while writing in Word, or looking at the web while working in DreamWeaver, or looking at JavaDoc while writing some code. We've all been through the move the window here - read - move it back over there, read the other window, etc. Having a two headed setup resolves that beautifully. And what clinches it is when you drag a window from one display to the other. It's like magic. Try it!