That's a must to finish all the exams before going to USA, and this is what I am going to do. And about the choosing the flying school, my friend has comeback a couple of days ago from American Aviation Academy in San Diego, CA, and I will talk to him and see what he says about them as soon as he has some free time. (You may ask: 'Why could you not ask him about the cost of doing JAA PPL in USA?', and the answer is because he's not from UK, and also how do I know whether he hasn't over-payed.)