The predicted release date for Fallout Online is 2012.
September 30th, 1997 was the release date of Fallout 1.
There are rumors of a Fallout 4 taking place in San Francisco, but as of 2/26/12 (today's date) there is no official news.
Haven - 2010 Fallout 4-1 was released on: USA: 13 September 2013
From what I can discover with a bit of web searching... An actual release date hasn't been given yet. Bethesda is planning a press conference on June 14, 2015 - and they've announced that the first full reveal of the game will take place on June 18, 2015. Therefore, a release date will be sometime after that date.
The Unfinished Nation - 2004 Fallout was released on: USA: 4 April 2005
Fallout Nuka Break - 2011 1-4 was released on: USA: 10 October 2011
Fallout Nuka Break - 2011 2-4 was released on: USA: 9 August 2013
Ax Men - 2008 Fallout Zone 4-10 was released on: USA: 20 February 2011
the compony in charge of the fallout mmo has not set a release date but it will probably be a while since they just got the rights to make the game and just announced it a month ago
It depends. After Fallout New Vegas's recent release and the announcement of Elder Scrolls 5, a Fallout 4 could be predicted to be released in 2012, at least. If that sells well, and Bethesda decides to continue the successful series, than there likely will be a Fallout 5.
Southland - 2009 Fallout 4-7 was released on: USA: 28 February 2012 Hungary: 28 February 2013 Finland: 28 July 2013