In a post today on the Playstation blog, Eric Lempel (director of PSN Operations) confirmed that firmware update 2.40 will bring in-game XMB access and enable trophies, among other features being announced soon. The post has no news of a date for the update, only mentioning that update 2.36 will come soon and bring with it system stability for certain titles.
Until then, fanboys can go over their friends houses who have the Xbox 360 and check out the features coming to the PS3, that have been available since the 360's launch.
UPDATE: Firmware update 2.36 is now live! The wait is on for 2.40!
