Hey Trout, 
All you should really have to do is plug it into your video card (which you may need a DVI to VGA converter to do) 
For Windows XP (and i think vista too):  
right click on your desktop, click properties 
select the second monitor, adjust the resolution, and check off extend my windows desktop to this monitor 
For Windows 7 (cause i cant remember what OS you're on): 
right click on the your desktop, click screen resolution 
Change Multiple Displays from Duplicate to Extend. Apply changes 
Then adjust Resolutions