When American citizens help their spouses to apply for immigration, they usually submit their applications to the US Immigration Service. The materials to be prepared include: American citizenship certificate, marriage certificate of two people, and proof of husband-wife relationship. Detailed materials are available at
/spview2.asp？ Id= 190 "application materials" column can be viewed, and the handling process is for reference.
Your husband can consult with local uscis or professional lawyers in the United States.