The State Department has announced that the 2009 Poverty Guidelines used for I-864, Affidavits of Support, went into effect on March 1, 2009. The I-864 is used for immigrant visa petitioners and joint sponsors. The guidelines are available here

All cases filed after March 1, 2009 are subject to the new poverty guidelines. Cases filed prior to March 1, 2009, use the guidelines that were in effect at the time of submission.