Have you ever had two documents that you needed open at the same time? If the answer is yes, then you could benefit from having two monitors. Consider it one point toward the green movement if it also prevents you from having to print out that first document.
So How Do I Do It?
Make sure you have the correct cables for the ports on your monitors and computer. Ports will either be classified as DVI, VGA, HDMI or Mini DisplayPort. Connect the second monitor to the laptop and turn it on.
Go to the Display Settings menu in your Control Panel. Click "Identify" or "Detect" (depending on which operating system you'll using) for the computer to register the second monitor. It often registers immediately without having to do this step.
Determine which setup you want. There are a few different ways to configure dual monitors, and you will have to adjust the settings to reflect the type of setup you desire. For example, you may want the second monitor to display the exact mirror of your first screen (if you're doing a presentation, for example), or you may want it to act as an extension of your desktop.
To have your monitor act as a mirror of your laptop screen, select "Duplicate These Displays" next to Multiple Displays option. Click "Apply."
To have your monitor act as an extension of your desktop, select "Extend These Displays" next to the Multiple Display options and click "Apply." You can then use your mouse to click and drag documents over to the second monitor. It's as easy as it sounds -- just select what you want to move, and drag it in the direction of the second screen, dropping it where you wish.
Click here to see these step-by-step instructions with how-to photos and screenshots.
Note: There is software that promises to help "maximize" the potential of multiple monitors. Although I haven't personally tried it, UltraMon is one that came highly recommended to me.