Be careful. Only training at a JAR registered facility or FTO given by the holder of a JAR FI(A) rating can be fully creditted to your training requirements. So you need to check the status of both the organisation and the individual instructor. If you choose to train with a non-JAR organisation or instructor, it may still be useful, but won't neccesarily contribute to your training minima.
You also need to be aware of the visa requirements for flight training in the US. A search in the Private Flying forum should yield the information that you need.