American studying in Britain?

I was wondering about going to University in Britain as an American. I know British Universities are significantly cheaper than colleges here, so it's something I want to look into. But I was wondering how the application process would work, considering that I haven't taken any British exams, so I don't have UCAS points or anything. Also, uming I moved back to the US after graduating, would my degree be transferable? I mean, obviously it will be if I study English, but what about something like Law School, for example? Since we have different judicial systems, would the degree only apply in the UK? If anyone knows anything about American attending British Universities, your help would be appreciated. :) Thanks!