I had to download an ISO. I don't have a optical drive. The first 2 I downloaded, bootcamp kept telling me it wasn't 64 bit and wouldn't load it. They were indeed 64 bit. I read somewhere it may have been a 32/64 bit combo download, so bootcamp got confused. I tried 1 last time to download another one and it worked flawless. The one that worked flawless was from the same link as one that didn't, so I don't know why one worked and one didn't. Maybe the first time it got corrupted is my only guess.
Anyhow... I had no trouble at all once I got past the 64 bit problem.
As for the guy that says just use parallels... I initially tried that first and it just didn't look very good. It was blurry and sometimes slow. Bootcamp looks great and works fast. It eats battery but it works just like I was on a windows machine.