回複:請問為母親辦理移民美國的問題:謝謝熱心人.
go to this website"http://uscis.gov/graphics/index.htm", lot of informations, you'll find all the answers there.
After they forward the documents to NVC(national visa center), then you go to "http://travel.state.gov/visa/immigrants/types/types_1309.html", to find more informations.