It looks like Peter Jackson's The Adventures of Tintin sequel is still on! Steven Spielberg directed the first movie, which ended up being a fantastic adventure film! The plan was to have Jackson direct the sequel, and that's exactly what he still intends to do. While speaking with BadTaste.it, the director confirmed that he will start work on Tintin as soon as he's finished with his Hobbit trilogy.
"As soon as I'm free of The Hobbit, I'll be going back into doing Tintin. It was held up by The Hobbit, but we have every intention of doing another Tintin movie and it's just waiting on me to be done with these Hobbit movies."
There have been rumors that the sequel will be based on a two-part story from the series, Seven Crystal Balls and Prisoners of the Sun, and that it would be called The Adventures Of Tintin: Prisoners of the Sun. There is also a chance there would be a third film, maybe even more possibly based on the Tintin book Destination Moon and Explorers on the Moon.
The script for the sequel has been completed, and it was written by Anthony Horowitz. The plot of the film apparently involves Tintin and Captain Haddock investigating a strange illness that has befallen seven explorers who have discovered an Incan tomb, before traveling to Peru to get to the bottom of the mystery.
I'm looking forward to seeing Jackson's Tintin sequel!