Jagged border around picture... Help

Hi, I was wondering if someone could help me achieve this effect... http://www.streamload.com/saeroner/Example.jpg I'm trying to get the edges of the Picture to look jagged like the one in the example... I know how to feather it in PS and I could probably do it manually, just wondering if there is an easy way... Thanks

1 - Duplicate original layer
2 - new layer
3 - with new layer selected, fill with whatever color
4 - use polygonal Lasso tool and draw the "Jagged frame", erase. now you have an idea of the final product.
5 - tweak
6 - Ctrl+click this layer thubnail then click "the eye" i.e. hide the layer
7 -click duplicated original layer
8 - Hit delete
9 - apply drop shadow or anything (use your creativity)
note: I prefer the use of shapes instead of selecting, because we have much more control on the final shape
Good luck