when does Season 2 on SHOWTIME start
Season 2: 2010
On February 10, 2009, Showtime Networks president of entertainment Robert Greenblatt announced that United States of Tara has been renewed for a second season, which will consist of 13 episodes and air in early 2010.
From: http://en.wikipedia.org/wiki/List_of_United_States_of_Tara_episodes