From my Hollywood insider, Hollywood Lou:

If you can believe it, Sony/MGM is doing Rocky 6. Shooting will begin in Philly in a few months. Sly will be back as Rocky who will find an up-and-coming boxer much like he once was and turn him into a champ. Basically, Rocky will be like Micky was to him. Hopefully Rocky will die in the end and crush all hopes of a Rocky 7 which would be Rocky punching out others in a retirement home.

Internet reports say Mr. T will reprise the role of Clubber Lang.