Ok, as i know and most people do, a laptop can be shown on another monitor because the monitor's screen is almost always bigger/better. However, i have a piece of junk monitor and may be getting a pretty good laptop w/ sxga screen. Now, can I display my computer on my laptop's screen???
Your best bet might be to try a program like this one. It was made to allow you to use one keyboard/mouse/monito for multiple computers. So net work the comps together, download the program, install the right part on both, then just don't set up the keyboard and mouse stuff. It should allow you to move your mouse to the edge of the screen like your scrolling off of the scree, then bump over the the other computer. So you should be able to use your laptop and desktop using your laptop monitor. I have never used it but give it a try.