Hi Franck,
Where are you living now ? Are you an EU citizen ? Do you hold FAA, JAA or "other" licenses ? Do you have a FI license ? It is quite easy to find an instructor job in the US if you have a work permit.
This forum is mostly for UK/EU jobs. It will be hard for you to find a job in the US on this forum. I suggest that you try some US forums. Also try
www.aeps.com. You might want to pay the annual fee, it is worth it ...
good luck.