In photoshop terms this technique is called "out-of-bounds".
(At least, I think this is what TTM meant :-) ?
If not, I understand this theme complétely wrong but I've enjoyed making this tutorial again anyway !!
I found two sites who discribe HOW you can make this.
HERE (English) or HERE (in Dutch)
First I pimped up the original pic. with a cute cherub and a flower'head' for the bird. Then I started with the tut.
Once finished I've add a texture and copied the background (blendingmode linear burn 78%) right beneath the out of bounds effect to achieve a more striking look.