Hi Marek. You might find this thread I started a few months ago handy. The guys were really helpful with some of my questions - and yes, it seems having a foreign ATP/L doesn't really matter that much over in the States, you'll need to do the ATP CTP course which I am currently looking at. Good luck.
Bugger. It appears I can't link to anything just yet. Look in my post history and/or search for the thread "ATP Course". Sorry!