http://documents.latimes.com/bungie-activision-contract/
Here's a SUMMARY if you dont' want to read the document.
Bungie has a contract with Activison to make 4 games, and 4 expansions(1 for each game).
Release will start in Fall 2013, with an expansion following in Fall 2014. Second game coming Fall 2015, with expansion in Fall 2016...etc...
The games are code-named "Destiny", and the expansions are code-named "Comet". This new Bungie IP is designed to help the transition into next-gen, which is why we're definitely getting Destiny #1 and #2 on 360,
Destiny #1 is being made for Xbox 360 and XBox 720(Fall 2013), a PS3 version will be considered if it is financially viable for release in Fall 2014.(1 year after the 360 and 720 versions.)
Destiny #2 will be made for XBox 360, 720 and PS4 and PC.(Fall 2015)
Destiny #3 will be for PS4 and 720 and PC.(2017)
Destiny #4 will be for Ps4 and 720 and PC.(2019)
