Applying to work as a physio in the USA

Hey, im a qualified physiotherapist currently working in Northern Ireland having graduated with a 4 year BSc (honours) degree in physiotherapy in 2008. I am extremely keen in musculoskeletal work and I wish to apply for work in America,particularly Boston.
I have been doing lots of research into working in the USA and I am aware of the exam and H1B1 visa. I have also been in contact with a recruitment agency,however some research has shown that agencies take a large cut off the salary and it would be better to try and sort documentation out independantly....any opinions/experiences of suggestions from fellow physios?

Has anyone had any experience of applying for work in the USA,particularly UK citizens? Any recommendations of how i should go about seeking work in America? How hard is the entrance exam?

Any help would be greatly appreciated

Thanks
Kx