Ain't It Cool News has what it says are spoilers for Tron 2 or TR2N or whatever it's called, based on anonymous sources. Here's a taste:
The movie starts in 1989. Kevin Flynn (Jeff Bridges) has created some of the world's top-selling games based on his Game Grid challenges in the first film, and has marketed the hell out of what he saw there (action figures, Recognizer night lights, etc.).
Flynn has a 7-year-old son named Sean.
Flynn disappears, leaving behind his son.
Alan Bradley (Bruce Boxleitner) takes over Flynn's company, ENCOM.
Jump forward in time: Sean is now twentysomething.
Alan Bradley has info that leads Sean to look for Flynn.
Light Cycles vs. Light Jets.
Click over to AICN for a lot more. The movie opens in 2011.