Have you used masks?
Have a picture.
Add a new layer.
You need a picture border (either free on some mags or make one up yourself).
Then add a amask to it.
Paint in the mask... white of black depending on how you set your mask to put a hole in the middle of your frame, yet crisp edges... play around a bit there.
Done.
There should be some tutorials for your fav post processing on layers. I use gimp.
