If you are a United States Citizen and married to an international spouse who is currently outside the United States, you may petition for an immigrant visa on your spouses behalf.
If your spouse is already in the United States in some non-immigrant status, you may be able to file an immediate relative petition and your spouse may be able to apply for permanent resident status. 


CAUTION: Depending upon the unique circumstances of your case; if your spouse entered the U.S. under a nonimmigrant visa other than a fiancee visa, this may possibly be seen by the INS as fraud for obtaining the wrong type of visa or for entering the U.S. under the wrong type of visa.
You should consult an immigration attorney if this situation applies to you before filing anything with the INS on your spouses behalf..

If you are a lawful permanent resident and your spouse is outside the U.S. you may also apply for an immigrant visa for your spouse, however there may be a lengthy waiting period for your priority date to become current.
If your spouse is already in the United States, you should contact an immigration attorney immediately to have you spouse's case evaluated to see if your spouse can apply for permanent resident status from within the United States.


Due to severe new laws about entering the United States under the wrong type of visa, the international spouse should not enter the U.S. under a prior non-immigrant visa.
You should contact an immigration attorney immediately for a case evaluation and to begin the process of obtaining an immigrant visa.

If your spouse is outside the U.S. he or she will be doing a "consular processing".
This means the U.S. citizen or lawful permanent resident spouse applies with the INS for an immigrant visa on behalf of the international spouse who will be interviewed later at a U.S. Consulate or Embassy in their country.
If approved, the international spouse comes to the U.S. under an immigrant visa and with permanent resident status.
Your success with either of these procedures will depend upon you and your international spouse meeting the eligibility requirements.
Whether you and your spouse are eligible for this immigration benefit will be determined by the INS (and the foreign Consulate or Embassy when doing a consular filing).