Heya Jon, if I may there are a few things you'll want to keep in mind. I've duo'd monitors, and I've set triples up for friends, but there are a few things you'll want to avoid. One thing is, duel monitors make a video card work harder, and that can/will translate to more heat. If you don't have a fairly high end card, make sure you install an extra fan on it. Even if it doesn't have a fan mount. You can take a drill, cut out a circle with a jig saw and a metal cutting blade create a nice space for it. I would definitely recommend doing this for triple monitors, unless your card is as snazzy as mine. Most cards upward of $200 will be ok with this, but you will still want to make sure you can keep it cool enough.
A cheap alternative is also to buy another pci card (assuming your system is new enough to support AGP and PCI and I'm sure it is. The majority of PCs available from standard retailers like Dell, Gateway, HP etc can not do this, because they cannot process multiple video cards that aren't running in SLI mode. If you find that your card isn't well suited to run 3 monitors off of it, then see if your card is SLI compatible, and buy an exact duplicate. This will enable 4 monitors (if you wanted) with relative ease.
Good luck, I hope it runs smoothly, let me know if I can donate any further geek to the cause lol.