The immigration laws of the United States permit the immigration of certain “immediate relatives” to the U.S. People who want to become immigrants are divided into categories based on a preference system.
The immediate relatives of U.S. citizens, who include parents, spouses and unmarried children under the age of 21, do not have to wait for an immigrant visa number to become available once the application filed for them is approved by the US Citizenship and Immigration Services. An immigrant visa number will be immediately available for immediate relatives of American citizen.
A legal immigrant is a foreign national who has been granted the privilege of living and working permanently in the United States. There is a process for your spouse to become a legal immigrant.
If your spouse is living inside the U.S., he or she may apply to adjust his or her status as a lawful permanent resident. He or she may apply for an employment authorization card immediately. http://www.criminalimmigrationlawyer.com/
If your spouse is outside the U.S., he or she may apply for his or her residency at the American embassy.