I would add to Mayflower's description that in my case, a couple days before the prep, I had to swallow & demonstrate that I could pass a patency capsule. This is a capsule slightly larger than the camera, but which unlike the camera, will break down if it gets caught in a stricture or similar gut abnormality. If this occurred with the camera, at best you'd be looking at some involved endoscopic procedure to remove it, and possibly surgery. In my case, the prep was basically the same as for a colonoscopy (3 liters of Colyte the night before, only clear liquids, etc.). I've done this prep 3 times now, and I know many find it very uncomfortable, but I find it more annoying than painful. I would suggest avoiding any of the nauseating artificial flavor packets that come with the laxative bucket. Without them, the solution just tastes slightly salty, like some kind of odd broth, which I personally find more palatable than the sickeningly sweet, artificial flavor alternative.
In order to give you an idea of size, here's a pic of a pill cam (yes, this is the ACTUAL camera I swallowed, and YES I did retrieve it from, well, you know... ). The pill next to the cam is a 500mg generic Tylenol (paracetamol/acetaminophen) capsule, they dose you usually take 2 of.
Hope this helps.
David