Is this an actual cactus, or some other type of succulent? Do you know the name of it? Also, how big is it?

Yes, it is a cactus. The closest I can come to identifying it is that it seems to fall under the Cereus-type category. It is about 2 feet tall.

Here's a picture, if anyone is a cactus guru.

Here is a link that might be useful: cactus

That may be a tough one to light. Most cacti need full sun in order to grow normally. And a two foot tall cactus has a lot more vertical surface area to light. Cereus may be a bit more tolerant of lower light, but I'm not sure. The best thing for it would probably be a metal halide, but that would be a bit expensive. You could try a couple of compact fluorescents. You can buy clamp on dish reflectors to put them in, or find a hanging fixture, or a lamp with rotating arms. It really depends on how you want to mount the lights. If you go this route, I'd keep any CFL within a foot of the plant. Also, look for daylight bulbs, preferably 30 watts or more (actual watts, not incandescent equivalent).