There's been a lot of rumors to what other movie Marvel Studios will be releasing in 2014. We know Captain America 2 is set for April 2014. Marvel has had a placeholder for another movie (at one point there was one listed for May 16 and one for June 27, which may have been removed for Cap 2 in April). There's been a few contenders for who will be featured and Latino Review is saying it will definitely be Guardians of the Galaxy.
Latino Review said this was supposed to be announced at Comic-Con, will have Thanos in it and lead up to The Avengers 2 in 2015. Head on over there for more of the information they've gathered on this.
This makes sense. We have heard that domain names involving the Guardians have been purchased. The team also appeared on The Avengers: Earth's Mightiest Heroes. We'll have to wait to hear what the official word from Marvel/Disney is.
Let's just hope Nova is in it, whatever it is.