In order to work in the USA you will need to obtain the CGFNS certification, information at www.cgfns.com.
Then you will be eligable to apply for the state boards. After qualifying from the Adult Branch program, I applied to the CGFNS, it took me 3 attempts before I passed, because 1) I didnt study hard enough, and 2) I did not have enough knowledge of Maternity, child health, mental health and American Nursing, such as Language differences. I passed the state boards first time, so it can happen. You will also need to get sposorship, and some agencies are advertised in the Nursing Times or Standard. You will also need to be Adult trained, as they do not accept any other branches or nurses. However, when you work in the USA, you can work in any area of nursing that you choose, such as Maternity or Mental Health or adult, you have much more selection than in the UK. Nurses here are much stronger than in the UK, primarily because of stronger unions, as the employer really listens to the unions. Nurses are expected to do alot more, such as listen to heart and lung sounds, so physical assessment skills are more important. The doctors relies alot more on the nurses assessment.. It is a culture shock and a really interesting experience. Good luck with your training. If you would like to ask me any more questions, then just ask, Emma