Angry Birds Walkthrough
Your key here is to hit at a place that instantly takes out the middle pig, and causes the other two pigs to slowly roll and fall off. This level is definitely doable in 1 hit, although it will take a few tries to get the right spot.
[youtube width=420 height=345 time=33]http://www.youtube.com/watch?v=0Yq0eleZmy0[/youtube]