If you already hold a UK ATPL, you will (according to FAR 61.153(d)3) be eligible to take the US test-- no need to get the US commercial and IR first. I seem to remember that the UK times reqquired cover those required for the US ATPL--you should go to faa.gov and check FAR 61.153-61.160 or so to ensure you have the required experience. The written should be relatively easy (go to faatest.com and get the software to study) then come to the states and do the medical (or do the medical with one of the FAA certified CAA doctors) and do a few hours brush up and the test. Many people use all-atps for this part, but any FBO with a twin should be fine since almost all (all?) DEs can give the ATP exam. You could also do it with one of the DEs in europe, just give them a call to ensure everthing is OK.
-me
ps. keep us posted on your progress!!!
[This message has been edited by Low_and_Slow (edited 23 March 2001).]