I did it 3 months ago at FSI Wichita during my C560 XL type rating.
First you need to validate your foreign CPL in FAA:
Airmen Certification: Verify the Authenticity of a Foreign License, Rating, or Medical Certification
It usually takes about 2 months.
Then you need to pass FAA ATP written test. I passed it at FSI Le Bourget. 1300 questions to learn (strongly recommend Gleim books). Piece of cake comparing to JAA ATPL.
Last part is to coordinate with FSI your ATP checkride with Type Rating checkride, to do it at the same time. Shouldn't be a problem.
Good luck!!!
Yogi