First question you asked I had a debate with someone on another forum about. I don't see a point in going over to the US to learn to fly just to save 2kish... and from an income point of view i'm not very well off.
Also when you go to convert your license from FAA to CAA approved you have to resit all your exams and do a few more hours with an instructor because the JAR-FCL requires more than an FAA PPL. A lot of hassle if you ask me.
Second question - I'd say read the airpilots manual 1 or whatever book the flight school/club require and get to know the exercises you will be doing, get a head start on the aviation law... but really learn as your going through the practical - you understand what your learning a little better.