According to Weekly Shonen Jump magazine, the second movie of Gintama
was announced to be premiered in 2013. It will be an original story written by the manga author. The scan says the airing of Gintama TV anime will start on October 4th. It's unclear whether the TV program will be a rerun or a new series.
Source: Scan of WSJ
Update Aug 26
According to the official website, the TV series to be aired from this October will be a rerun of the previous series with additional new episode(s).
Source: Gintama official website
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Second Gintama Movie
2012 Gintama TV series