http://uscis.gov/graphics/formsfee/forms/i-140.htm
If the alien's employment will be in Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, New Mexico, North Carolina, South Carolina, Oklahoma, Tennessee, or Texas, mail the petition to:
For I-140s filed concurrently with Form I-485:
USCIS Texas Service Center
P.O. Box 852939
Mesquite, TX 75185-2939
For I-140s filed alone:
USCIS Texas Service Center
P.O. Box 852135
Mesquite, TX 75185-2135