If you want to hour build its a paperwork excercise, if you wish to add FAA ratings its a skills test. (unless its changed since I was there)
If you have a CPL / IR you should be able to convert to the FAA with flight tests and a little training, for PPL a small fee and a visit to the District standards office and the US embassy before you leave.
E mail one of the US flight schools or visit FAA website.
Or ask Keygrip, just noticed hes in FL