We haven't heard a peep about a launch date. Moore says we will definitely see Madden on the Facebook platform, but the social media version will be simpler than its console cousins, because EA wants to "make Madden more accessible."
Facebook games are a big deal these days. FarmVille and Mafia Wars developer Zynga just raised $180 million in funding. The news that established (but more niche) long-time video game franchise Civilization is coming to Facebook this summer has gotten a lot of press and interest, too.
More presciently, EA just bought a huge Facebook game company called Playfish for $400 million. The quote from Moore about EA's Madden plans didn't mention Playfish, but it's possible that the acquired company's resources will be used to develop and publish Madden on Facebook.