I don't really have time at the moment to come up with an actual tutorial so the best i can do now is explain using words until someone or myself uploads images.

1. Create New Layer.
2. Use the Pen Tool and create the fold.
3. Right+Click and select Make Selection.
4. Fill the selection with white if you want the bottom of the paper to be that color.
5. With the selection still there, create Another New Layer.
6. Choose the Brush (make sure it's the soft edge type) or the Gradient tool (Solid to Transparent).
7. Where the straight line is located nearer to the corner, you'll need to make a 'shadow' there using either the Brush or Gradient tool. Your image was a good reference for lighting.

8. Deselect the selection.
9. Now that you know where your fold is, you take your Pen Tool or Lasso Tool and select the excessive area you'd like to hide to create the fold. In this case, it's the corner area there.
10. After the selection is made you either Deleter or use the Mask on the real image and hide that part just in case you'd like to use it for something else.
11. Deselect after you're done.
12. Create Another New Layer and Move this layer beneath the actual image.
13. Use the Brush or Gradient tool again and make the needed shadow from the straight line nearer towards the corner. What you're trying to do is mimic the shadow beneath the paper.
I know it sounds confusing but I don't have the time to do the screenshots at the moment or create a better tutorial so I hope this'll help you make your way.

Cheers.
This post has been edited by etsuko: Apr 4 2006, 05:06 PM