Up until iOS5, the process of sharing to Facebook was a long-winded one, just like we've done in the last few recipes: setting up Facebook apps, writing code to implement login and authorization, and finally posting to a wall.
Thankfully, in iOS support for Facebook and Twitter is now baked into the OS via the Settings app. A user can connect to Twitter and Facebook once, and applications can then ask to access their social accounts. Once granted, an app can access the social accounts to post content on behalf of the user. If you've ever clicked a share button in iOS and seen something like this, you're using the built-in Twitter/Facebook support.
This means we can replace most of—not all—the code in the previous recipes with a few lines that can achieve the same thing, allowing us to post to a Facebook wall or send a tweet with a photo attached.