The Department of State has issued its Visa Bulletin for August 2009. The Bulletin sets forth immigrant visa number availability for August for qualified visa applicants in numerically limited visa classifications.
The Bulletin lists cut off dates. If an applicant has a priority date (generally the date of filing of the petition or an application) earlier than the cutoff date, then the applicant may be allocated a visa number.
Please see the August, 2009 Visa Bulletin at http://travel.state.gov/visa/frvi/bulletin/bulletin_4539.html