Warners developing "Terminator 4" feature, "Terminator Salvation: The Future Begins" will start shooting early 2008 from a screenplay by John Brancato and Michael Ferris.
Following "Salvation", producers are looking at a 'revised' storyline leading into two additional films.
Actor Arnold Shwarzenegger appeared in three previous "Terminator" films.
"We've left it open for him to maybe do a cameo", said "Salvation" executive producer Moritz Borman.
"Terminator Salvation: The Future Begins" will be released summer 2009.
