Terminator Salvation has no number
There's an article online about the new Terminator film, and while it gives us little in detail it does tell us the title of the new film and also confirms the timeline that this will take place in.
The new title is Terminator Salvation. Note that there's no number in there because the studio want new franchise to be separated from the existing, and a lot of that is about the timeline in which the story exists.
Terminator Salvation will, according to the Producers, carry the scale and size of Terminator 3: Rise of the Machines, but not the budget. That's not hard to do since reports are that the budget for that film, which Variety have at US $200 million, was inflated due to rights payments and a complex financial structure.
Warner Brothers now has distribution rights for the film for North America and talks are now in progress to obtain worldwide distribution, with some territories already bought.
The story then goes into some rather boring recap about the whole film, but what is interesting is that they have confirmed that the timeline for this Terminator will occur in the future, during the full scale war of humans and SkyNet. One of the Producers said:
“The third film was really the conclusion of what happened in the 'now.' You will find the most-loved characters, but the intention here is to present a fresh new world and have this be the first of a trilogy.”
That's interesting, you will find the most loved characters, although be aware that doesn't say actors. When asked about the return of Arnold Schwarzenegger they were cagey, it seems that depends on desire, availability and the Director. Okay, so that's a big fat no then.