Hello There,
Your query about what kind of hoops you need to jump through + what kind of paperwork you need to have in order to work in North America has been answered several times. Actually your query almost rates as a FAQ.
I don't know if you are looking for opportunities in Canada or the USA.
Warning: be prepared for some rude messages from regular posters to the board. Some guys will help you out, while some guys will tell you to stay home. Best of Luck to You!!