Beginning Aug. 3, 2010 all Form I-129F petitions being filed by a U.S. citizen on behalf of a fiancé(e) or spouse must be submitted to the USCIS Dallas Lockbox facility.
For U.S. Postal Service:
PO Box 660151
Dallas, TX 75266
For Express mail and courier deliveries:
2501 South State Highway 121 Business
Lewisville, TX 75067
Detailed guidance can be found in the updated Form I-129F instructions online at www.uscis.gov (click on the Forms tab).