The man who voiced Jarvis in all the movies featuring Iron Man, will play vision in The Avengers: Age of Ultron.
In the comic book world, Ultron was created by a man named Hank Pym, also known as Ant-Man. Vision, a synthetic humanoid like Ultron, was created by the super-powered sentient machine to battle the Avengers. In time however, Vision defected from his master, betrayed his original programming, and as a result joined the superhero team. Age of Ultron will tweak some of these story elements, while still maintaining the strong character development the characters of the Avengers movie have established up to this point.
The movie will likely make Tony Stark the brains behind Ultron's creation. Following some type of conflict, Ultron will betray Tony, and create his version of Vision by hacking Jarvis, Tony's artificial A.I, and putting him into a shell of some sort (perhaps another Iron Man suit, or an entirely new body created by Ultron himself). Because Jarvis knows everything there is to know about Tony Stark and his alter-ego Iron Man - not to mention the Avengers group itself - this sets up some highly entertaining possibilities when it comes to how Ultron will approach the battle against the Avengers, and what aspects of Tony's life he uses to destroy his maker.
The Avengers: Age of Ultron is set for a May 2015 release.