The USCIS has announced that effective January 1st, 2012, it will begin accepting stand alone I-130 petitions at two different lockbox locations. The I-130 petition is used to file for an immigrant petition based upon family relationships, such as being a spouse of a U.S. citizen, child of a U.S. citizen, parent of a U.S. citizen, and sibling of U.S. citizen.
The form will not be received at both a Chicago and Phoenix lockbox, and at a different location from where the I-130 is filed when accompanied by other immigration petitions. Failure to file at the correct location will result in a delay of the petition being processed (and its possible rejection).
If you are seeking to file an I-130, please contact a family immigration lawyer.