**FILE** Sen. Barack Obama, D-Ill., top center, signs autographs for supporters in this file photo from May 6, 2006, after a speech in Omaha, Neb. A fundraiser for the Democratic presidential candidate Barack Obama in Omaha next week is hardly the beginning of the relationship between billionaire investor Warren Buffett and the Illinois senator. Buffett and others are co-hosting the 500-per-person event reception Aug. 15 at the Ironwood Country Club. An earlier reception will be held for those who contribute $2,300. (AP Photo/Dave Weaver)