According to a source at TheSixthAxis, which they seem to be pretty sure of, the PlayStation 3 will be getting “a popular 360 favorite” which will “be released towards the end of the year.” Unfortunately, they were unable to share specifics with us, but they’ve said that they’re “promised more information in roughly a month’s time”.
The studio is also said to have other exciting news to share soon enough.
As for the Xbox 360 “favorite” moving to PlayStation 3, we can only think of Mass Effect or Left 4 Dead as possibilities. Most of the Xbox 360’s big titles which can be considered favorites are published by Microsoft, such as Gears of War, Halo, Lost Odyssey and Crackdown.