[FONT="Comic Sans MS"]I'm from the UK too - I qualified in 1987. I was out of nursing for about seven years, having never worked in the US.
Anyway, I approached the State BoN who mailed me all the necessary forms - you have to get transcripts from England relating to your RN training and any other relevent qualifications. You also need a green card or work permit, and have to get finger printed etc. for the police check. After all the info was amassed, the BoN gave me "authority to test" - it took about nine months.
I studied for the NCLEX for about 6 months using the Saunders review and a Kaplan book (but there are courses you can pay for to help you get through the test).
I arranged to sit the test and passed in January '05. Then I looked around for "refresher courses", which were few and far between - I enrolled for a classroom course that lasted about a month, but really it was a waste of time (and money) because there was no practical element.
I gained a job at my local hospital on med/surg and was lucky enough to be able to join the new grads for an in depth orientation (six weeks). And have been there ever since (although I experienced quite a bit of "health culture shock")!
I work with a few "back to nursing" RNs, from many countries. The hospital is also willing to train people other than during the new grad orientation, usually for as long as it takes (within reason). There is such a shortage of nurses here...
Having trained in the UK, you will have a lot of practical experience, which is an invaluable asset, compared to those who spent most of their course in the classroom.
Lots of things are different - like RNs have to start IVs, do physical assessments and are responsible for doing everything for your assignment of pts (including PO and IV drugs), and computer charting. Also, there is a huge focus on "customer service" and not getting sued!
Best of luck - it's worth the struggle (pay, benefits, job satisfaction etc.)
Go for it!