Depending on where you are planning to work, you will need to either obtain the NCLEX exam or the CGFNS exam. Most states require that you take the CGFNS exam before you can sit the NCELX.
www.cgfns.com is the website to go to for that one. You should probably decide where you want to go, and then call that particular board of nursing, they will tell you what you need, and advise you. If you are from the UK, then you will be familiar with how poor the wages are. In the USA the wages differ from state to state. You would be wise to check out the standard of living in certain areas before you choose. In Minnesota RN's start at 18$ an hour, which is about 13 UK pounds which is good I think. Although the winters are pretty cold, the summers are very hot.
www.nclex.com is a useful website, that should tell you everything you need to know. As far as employers go, you will need to find a company which will sponsor you. The Nursing Times magazine has an international section at the back, which sometimes lists companies in there. GOOD LUCK AND I HOPE THAT YOU FIND THE SUN, EMMA