Rumor has it that Bryan Cranston may be getting a role in a future Spider-Man movie. He could potentially play the role of Norman Osborn in several Spidey movies, as well as other Marvel Cinematic Universe projects.
At least, that’s what Geekosity’s usually reasonably reliable Mikey Sutton says. Importantly, Cranston should play the role of Norman Osborn, but possibly not directly the Green Goblin.

Norman Osborn
Mikey Sutton stated that the idea at this point would be that Bryan Cranston will play the role of Norman Osborn. He cannot be seen as the Green Goblin, who we have now seen twice as the villain in one of the Spider-Man films.
According to Sutton, it cannot be ruled out that this would be the case at a later time, but it is not yet an issue. Instead, it would not be considered until a much later time.
Finally, Sutton states on the basis of his anonymous sources that Peter Parker looks very much up to Norman in the films. So that could be interesting, if the rumor is correct.