Photoshop
Tutorials -> Old Paper - difficulty :

INFORMATION : This tutorial is also aviable as a video-tutorial : DOWNLOAD
At first you have to create a new image with a size abou 400x400 pixel. The
background should filled with a dark color like brown or grey to see the more
light paper. After that you have to create a new layer ( Layer -> New ->
Layer )
Now you have to create a selection which will later be the size of the paper
and fill this seletion with #FFFFFF ( white ).

Youe need a brush for the next step. You can download the brush named „Old
Paper 1“ at www.prettybrush.cjb.net
or from the following link ( Link
).
Take the Brush-Tool (
) and fill the selection
with the 5th brush of the collection and a medium grey color.

This brush is only an example i like to use, of course there a many othe possibilities to make the paper more realistic.
Now you have to open the Blending Options. At first you have to mark "Drop Shadow" ( Opacity : ca. 35 % ; Angle : 120 ° ) and then "Stroke" ( 1 pixel, black, Opacity : ca. 30 % ).
I added some other brushes in this picture.
The next part is a little complicated. At first you have to zoom the image
to about 700% an then take the "Lasso-Tool" (
). You now have to use the tool an mark some parts of the paper, the form doesn't
matter :

You have to delete the selceted parts and some realistic tears will appear in the paper. You can use this method on as many parts of the paper as you want to. My result :

The paper is now ready. Of course there are many other tings you can change to make it look more interesting, but the main-concept should be clear. Have fun with it!
( If there are some mistakes in the tutorial, please tell me... )