kkay
An FAA Dispatchers Licence will not get you the right to work in the US, unless you already have the right to work there. The official purpose of the licence is only good for those who have the right to work in the US and want to work there. The Licence will give you a good understanding and starting step into the world of dispatching and a nice shiny card (if you pass the course). I say that as a UK born citizen (without the right to work in the US) who has the Licence.
If you do decide to go ahead with the course I can tell you that I would recommend Sheffield School of Aeronautics in Ft. Lauderdale. I attended there and was very impressed. I know that others will tell you different (probably those who didnt pass the course - and there were a few!), but in my opinion they were excellent. DO NOT expect to pass the course and then get a job in the US. If you don't have the right to work in the US, IT WON'T HAPPEN!