dnt need a tut. for that. just a bit of common sense...
I had a go.
Open your image, duplicate it.
Drag this onto a new layer ( colour of your choice)
Hit M...make your marquee around where you want the frame to be, right click and add a stroke of approx 30 pix.
Merge the 2 layers.
Add a vector mask to the top layer and rub out around the frame , parts of the image you don't want.
.....thats how I did it.
cs3 + common sense I guess.
My quick go, I'm not good at these layer mask things.
I messed that one up - horse not in line... tried again!!