Inside Out

Updated Synopsis from CinemaCon 2012
Here is an updated synopsis from the Disney panel at CinemaCon on April 24, 2012: "Pixar takes audiences on incredible journeys into extraordinary worlds: from the darkest depths of the ocean to the top of the tepui mountains in South America; from the fictional metropolis of Monstropolis to a futuristic fantasy of outer space. From director Pete Docter (Up, Monsters, Inc.) and producer Jonas Rivera (Up), the inventive new film will take you to a place that everyone knows, but no one has ever seen: the world inside the human mind."

There is also good information that Michael Arndt is working on the script (from Big Screen Animation).

Details Announced
Pixar has announced details on it's second original movie at the D23 Expo.

"From director Pete Docter comes an inventive new film that explores a world that everyone knows, but no one has seen: inside the human mind."

Directed by Pete Docter

Co-directed by Ronnie del Carmen

Produced by Jonas Rivera

(via The Pixar Blog)