You don't need anything more than what you currently have.
Enable "Home Sharing" on your Apple TV and on your iPhone. Then use the mirroring feature via AirPlay on your iPhone or iPad to send whatever app your want onto your TV.
It's not really amazing or anything. It's literally a mirror of what's on your device. For example, the iPad looks better simply because it's a bigger screen. But it does work. I just tried it a second ago. Works fine.
Once OS X Mountain Lion is released, you'll be able to do it directly from your MacBook Pro (assuming your MBP can handle ML).