Tilde...

I'm still really learning in Photoshop, but the torn edge filter is under filters>sketch>torn edges. I use the freehand l***o to make a jagged edge where I want it "torn", then bring it around the outside of the image so that the area I want gone is selected. Then I hit delete to blank that area out. Then I just messed around with the filter and colours until I got it looking like a torn edge....although I haven't managed to get it looking like I want yet, lol