sainty,
it's great to see such enthusiasm. but there is a dont run before you can walk thing here. take note of the above post. top bit of advice given is to get a copy of lasors and inwardly digest the contents. tis available free from the CAA website. it will give you a greater understanding of how difficult/rewarding this industry is.
as for working the states, they require pretty much the same level of experience as the UK before they let you loose as an instructor. the only befenit to the states is the relatively lower cost of training. however, unless you have the right to work, or can secure the relevent visa, you cannot work there.
to work in europe you need a JAA licence. to work in the states you need a FAA licence. you cannot work in the USA on a JAA licence, you will need a FAA licence, and vica versa.
best thing you can do is talk to your instructor. they will have trodden the path you want to take and will be happy to explain what is required.
good luck anyhoo.