Yes, you can get video input. You're going to have a full PC at your disposal after all, and there's little you can't do from that position
You will need a capture card or video card with capture capabilities, such as ATI's All-In-Wonderseries. I'm not too knowledgable about these cards, someone else might be able to point you to the best solution, but this at least will give you an idea.
Cool, thanks for the info. After some further research I saw that some screens have s-video/composit inputs in addition to VGA, so I'll go for one of those.