I brought my cat over from the US, and just went to my regular vet. She'd never done anything with the PETS scheme before, though, so we were guineapigs. Guineacats? Anyway, she enjoyed the learning process as much as I did, and we gathered paperwork, advice, recommendations as we went. That was immediately after PETS went into effect, so perhaps by now more vets are experienced in it. The only restriction when I did it was that only one lab in the US was authorized to test the cat's blood sample -- I think it was the University of Kansas? My vet packaged up the vials of blood for me and we shipped them Next Day Air with no difficulty. Again, this may have changed over the past year or so, and possibly more labs are authorized now.
It took a lot of research, work and MONEY, but I can honestly say that I would never have made the move if I couldn't have brought Willie (see pic).