According to the official website, the second season of Baka to Test to Shoukanjuu
was announced. More details will be revealed later.
Source: Baka Test official website
The novel author Inoue Kenji
posted an April Fool's joke "Baka to Test to Shokanju in Hollywood" in his official blog, but there is no connection between his joke and the announcement in the official website.
Updated on April 2nd
They announced the second season on the official website once again on April 2nd.
Updated on January 22nd 2011
According to Monthly Shonen Ace, the second season will be aired this summer.
Source: Scan of Ace