Can anyone point me to a tutorial on how to get that "torn edges" look on pictures? Thanks!

You can do a Google search for "tutorial mask torn edges". That will give you a lot to read. There are a lot masks to download from different placec like this one...

ook, do you want the image to look like it was torn in two? (such as if in rage you tore a photograph apart...)

I did a little "step-by-step" awhile back in the 2D forum (before i was mod here...) that may be of some help.

here's the link.

draw in edge in almost-white
add drop shadow
make shadow into layers
erase inappropriate bits (places it shouldn't be)
texturise almost-white edge