I see his upcoming appearances on that website
(I'm giving away one of my secrets
). I look at it occasionally. As for the tickets, you can buy them on the official website of the talk show.
As for when he will be on... if you look at his previous appearances :Larry Crowne
was released on July 1st and he was on talk shows between the end of May and the end of June.Angels & Demons
was released on May 15th, and he was on between between May 8 and May 15.
So I would say it's generally during the two weeks prior to the release date.