Mario & Luigi: Bowser's Inside Story

Mario & Luigi RPG 3 (tentative title) is the upcoming third title in the Mario & Luigi series. It was confirmed on October 2 at the Fall 2008 Nintendo Conference and will be released in 2009 for the Nintendo DS. The shown footage was very short, but one could see a giant spherical Toad rolling on the screen, Mario and Luigi using a Green Shell on a green bug-like enemy and Bowser using Fire Breath on two tree-like enemies. Supposedly, the story takes Mario and Luigi across the Mushroom Kingdom to solve the mystery of and find the cure for a deadly disease plaguing the land. This may explain the giant Toads in the hospital. It may also be the reason the brothers are exploring Bowser's body systems.

Characters
So far, these are the confirmed playable characters:
 * Mario
 * Luigi
 * Bowser