I recently came across this article, Not a foreign concept? Be humane when firing workers who aren't citizens, published in 2002 by the American Bar Association addressing the layoffs of foreign workers during reduction in work forces.
Considering today's financial crisis, the issue of foreign worker layoffs unfortunately becomes relevant again. Employers of foreign workers should be aware of not only their own obligations with respect to layoffs, but also mindful of the additional burdens placed on foreign workers during reductions of the work force.
See also my earlier entry on TN Visa & Layoffs.