Photo geek here.
I use a
Canon EOS Rebel (link is to Amazon's page for it. Mine's pretty much the same, but it's black). I got it used at a local camera store for somewhere in the $100-$150 range. It's pretty good, but I'm sure there are better. I haven't had any problems with it... it's pretty simple to use (but then again, I was taught how to use a manual camera in school, so...). In fact, I shot a roll tonight with some friends. I would like to get a longer lens for it, but that can get expensive. :\
Other than that, you'd also need film (obviously
), which you can push if you don't get good readings with the light meter while trying to shoot a picture, which you might not have a problem with since it's a wedding and most likely will be well-lit. I've used Kodak Tri-X 400 (I pushed it to 1600 tonight), Kodak TMAX 400, and Ilford 400. Pushing it will add grain, though, and can make something that looked really pretty when you shot it look less-than-awesome, which is unfortunate but sometimes you gotta do what you gotta do.
Instructions on how to do this may come with the camera, but it probably won't be under "pushing film." To push film, you basically change the ISO (this should definitely be in the manual) to a higher speed. For example, if you have 400-speed film, you could push it up to 800 or 1600. Pushing it to 800 is called pushing it one stop (and never works with my camera, go figure
); 1600 is two stops. You never want to push it above 1600, and likewise you never want to pull film (IE lowering the ISO). Pushing just tricks the camera into thinking you have faster film.
Also, if you think you need a flash, you shouldn't use the one that comes built-in with the camera, because it'll bring out the shadows more and make it ugly. I use a desklamp that bends so I can position it wherever I want and put a pillowcase over it to make the light softer. You might not be able to do that, though, so I'd recommend getting a flash that can plug into the top of the camera and point the bulb upwards so the flash will bounce and make things look more natural. I'd read the manual about flash shutter speeds, because I think that can vary with cameras (the school-provided one I used one day had a flash shutter speed of 125, for example, and I wasn't able to use my EOS Rebel, for whatever reason). But like I said, since it's a wedding, there should be enough lighting there.