If no refusals or additional requirements are identified or if all identified issues have been resolved, the examining attorney will approve the mark for publication in the Official Gazette (OG) , a weekly online publication. The USPTO will send you a Notice of Publication stating the publication date.

If you have authorized e-mail communication, the USPTO will e-mail you a "Notification of ‘Notice of Publication’" approximately 3 weeks before the future publication date in the OG . On the actual publication date, you will receive a second e-mail, namely, " Official Gazette Publication Confirmation" with a link to the OG . If you have not authorized e-mail communication with the USPTO, the USPTO will mail you approximately 3 weeks before publication a paper "Notice of Publication" stating the publication date.

http://www.uspto.gov/trademarks/basics/BasicFacts.pdf