Fusion: Jailbreak Tweak Integrates Facebook into iOS 5.x
Apple's effort to bring Facebook integration in iOS 4, which had to be shelved as both companies did not come to an agreement and ended up deeply integrating Twitter into iOS 5.
If you're a Facebook user and miss the ability to quickly and easily share everything that's happening in your world to Facebook then we've some good news.
Fusion is a new jailbreak tweak that allows you to post to Facebook from the Twitter sheet. You can also post to Foursquare and MySpace.