Valve has announced an agreement with Rockstar Games to make Rockstar's entire PC game catalog available for digital download through its Steam content delivery service.Titles now available for download includeandThe agreement between Rockstar and Valve is similar to one Rockstar recently announced with IGN Entertainment's digital retail store, Direct2Drive.Said Rowan Hadaj, head of finance and corporate development of Rockstar Games, "We were immediately excited by the opportunity to offer our PC catalog via Steam because it allows us to reach out to gamers around the world in exciting new ways. We are continually looking for ways to give back to our fans and this collaboration will give people a chance to easily revisit some of our greatest titles."