ATLANTA (AP) --- Newt Gingrich, the House speaker who led a national GOP resurgence in the 1990s before facing ethics questions and resigning, is running for president. Gingrich's announcement, made on social networking websites Monday, came after months of public flirting with a bid. He enters a slow-to-form GOP presidential field that has left some Republicans craving more options as they search for a nominee strong enough to credibly challenge President Barack Obama. The former Georgia congressman, well-known to most Republicans, brings to the race a years-in-the-making political machine with ties to early nominating states as well as a network...