Taxes? US citizen/foreign firm/work abroad
 

I am hoping someone could explain with some certianity my us tax obligations, if I reside in the US, work abroad (outside US or Canada) and are employed by a Canadian firm (paid in Canadian currency). In addition, will I continue to participate in the US social security program (payroll deuctions via a treaty with Canada?). I suppose there are other Americans in the same situation that may be easily able to answer the questions. Thank you in advance.