I'm cluesless on how to do this in photoshop or psp, but I bought a little application called Stichwitch for this very reason and it works quite well.

It lets you lay a splice on your uvmap, then pick an image to run along the spline.  All you need then is some stitching images to get a sewn seam.  It has all sorts of options to lay down shadows and suchlike to make things look good.

John

Fugazi (without the aid of a safety net)

https://www.facebook.com/Fugazi3D