This has been answered a million times here on Pprune. Search for piggyback license and FAR 61.75.
But basically you need a FAA validation of your JAA licence. It takes time and you have to pay CAA to release the info. Then you pick it up at a FSDO in the US, get a BFR with the school and off you go. If you need it for Sept, start yesterday.
Last edited by AdamFrisch; 19th Jul 2012 at 02:28.