Actually I have a desktop and laptop and I want to run dual monitors on the desktop, using the laptop as the second monitor. Or just hooking up a second monitor.
I am not sure if you can use a laptop screen as a second display for a desktop machine. As for dual monitors on a desktop, well you need a compatible card to start with, and then you simply right-click the desktop, click the settings button for your graphics card and follow the instructions.
I looked into this a while back, I don't know now, but back then it seemed to be sluggish, even with only 24 bit colors, so you may want to invest in Gigabit networking, but by all means, check out the trial.