The cost I have given you includes everything from flight training costs to airfares, US medical insurance, car insurance checkrides the whole lot. Many of the costs that have been quoted in this thread are simply not realistic. For example, I've seen the ATPL ground as costing just 1200. To do it with a reputable school would cost 1800; add in 800 for exams; add another 3000 for living expenses and hotel accomodation and you get a long way from the 1200 that someone mentioned. I reckon that I've spent about 15,000 on FAA flight training, another 14,000 will be spent on the conversion, which includes converting the CFI to FI. When you start to add living expenses in, the figure creeps towards the 40,000 mark. Of course living in the UK is not free so I'll probably save 15,000ish on a UK ATPL course.
Also, as an aside I noticed that Seaweed Knees mentioned logging safety pilot time, whilst flying with pilots who are under the hood. Fine for the FAA but as far as I know the JAA do not allow this time to be logged. Perhaps I'm mistaken.
Also, if you do the ATPL theory after the FAA training then your skills will become very rusty and the conversion will be VERY expensive. I've said it before and I'll say it again, do the ATPL's after the FAA PPL or you are in for trouble!