Job listings posted by EA appear to confirm that a new game in the Army of Two franchise is on the way.
Visceral Games Montreal - formerly EA Montreal - is once again handling development. The studio "is seeking a dynamic Senior Producer for the Army of Two franchise" and a "talented Lead Environment Artist for the Army of Two franchise".
The second game - Army of Two: The 40th Day - was released in January 2010 to generally positive reviews. In May that year EA announced the game had sold through over one million copies.
There's been no official word on a sequel.
If EA's hiring then it seems pretty much nailed on that we'll get a new game, but when will it be announced. The nature of the roles suggests that the project isn't currently very far along, potentially ruling out any kind of reveal at E3 this year.