Believe it or not, Facebook has just released an official Poke app for the iPhone.

The app lets the user send a photo to another user which is only be viewable for a short time. Something like a self destructing bomb in Mission Impossible.
Poke your friends to share fun moments or just say hello.


• Poke a friend with a message, photo or video
• Choose how long they can see it
• Press and hold to see pokes from friends
• Say where you are when you poke
• See when your friends take screenshots
Facebook Poke, iPhone: FREE
Source:
http://discovr.smashpop.net/2012/12/26/facebook-releases-new-poke-app-for-the-iphone/