This might be an obvious tip for any would be immigrant, but it may still be useful to refer to. Every year a few of the green card applicants are chosen to get a permanent residence in USA. There are various companies selling green card application service for rather hefty prices (such as USFIS, USGIS etc.) by trying to simplify the process. However, officially, applying is completely free and all the information is on the USCIS (US Citizenship and Immigration Services) site: http://www.uscis.gov/greencard