Mplayit has launched a Facebook app called iPhone Arcade, which aims to let people preview iPhone games before buying them.
The app, which can be found here, is actually an offshoot of Mplayit's existing Mobile Arcade app on the social network.
Right now, it offers an interface to watch YouTube video demos of a wide selection of iPhone games. This, of course, is something that's missing from the App Store itself, which only offers screenshots.
Each game has a button to click through to buy the game, as well as a share button to publicise it in your Facebook feed. However, unlike the non-iPhone version, you can't actually play embedded versions of the games.
Perhaps that'll come later - iPhone Arcade is still in beta, after all.