The IRS has posted a website link to Revenue Ruling 2012-24, containing the applicable federal rates for September. (The IRS released these rates on August 21, 2012, but did not post a link at that time.) These rates are used for such purposes as calculating distributions from retirement arrangements that meet the substantially equal periodic payment requirements of IRC Sec. 72(t)(2)(A)(iv).
Revenue Ruling 2012-24 may be accessed at the following link.
http://www.irs.ustreas.gov/pub/irs-drop/rr-12-24.pdf