McG Is Developing Terminator 5
It has already been reported that Terminator Salvation is the first film in a planned trilogy and that Halcyon has a thrill picture option on star Christian Bale to reprise the role of John Connor in the two sequels. Variety reports that development on a Terminator 5 has already begun with direct McG heavily involved in the process (although It wasn't made completely clear if he has officially signed on for the fifth film just yet).
Halcyon had originally planned to wait until the release of Terminator Salvation before moving on to the next film, but the early reaction from moviegoers, the studio and press has resulted them to greenlight the development early. The current plan is to have Terminator 5 (working title) in theaters for 2011 (presumably Summer). The announcement was made at the Dubai International Film Festival, and while no locations have been picked for the next film, the Middle East was mentioned as a possibility.
source: Variety