Update: 11:52 am EST: Reports from Fox News, The Washington Post, Politico, and others are saying that Newt Gingrich will suspend his campaign next Tuesday. Politico's Ginger Gibson reports that "Gingrich is waiting until Tuesday to allow family and staff who are currently spread around the country time to travel to D.C. to participate in the announcement."
Update 10:54 a.m. EST: CNN has word that Gingrich will officially end his campaign in a Washington, D.C. event on Tuesday, after which he will start figuring out how best to support Romney. Interestingly, that's not necessarily framed as an endorsement. Per CNN's Mark Preston:
"When he says he is transitioning, what he means is that he is trying to determine as a citizen how he will pro-actively help Mitt Romney become president and the Republican Party win back the Senate and help (House Speaker) John Boehner keep his majority in the House," said one of the sources, who spoke on the condition of anonymity.
Update 10:47 a.m. EST: It's worth remembering that Gingrich has been hinting at an end to his campaign for a few days now. On Monday, he told NBC News, "I think we need to take a deep look at what we are doing," and said he would "reassess" his campaign depending on how things turned out in Delaware, a winner-take-all primary. Of course, Romney won there handily, also picking up Connecticut, Rhode Island, Pennsylvania, and New York.