I strongly suspect the next movie is going to take place in a [pre-Judgment Day] 2011," McG reveals. "John Connor is going to travel back in time and he's going to have to galvanize the militaries of the world for an impending Skynet invasion. They've figured out time travel to the degree where they can send more than one naked entity. So you're going to have hunter killers and transports and harvesters and everything arriving in our time and Connor fighting back with conventional military warfare, which I think is going to be f%$^&%ng awesome. I also think he's going to meet a scientist that's going to look a lot like present-day Robert Patrick [who famously played the T-1000 in Terminator 2], talking about stem-cell research and how we can all live as idealized, younger versions of ourselves."
We all knew they were going to try and squeeze a trilogy out of this newly rebooted franchise. I have to wait to see Terminator Salvation before I can say I want another one, but just from the trailers and everything else I have seen from this movie a sequel is inevitable.