I like this site for chess stamps.
http://www.queensac.com/positions.html
There are a lot forgeries depicting famous chess players on stamps.
This site has most of them listed. I'm sure I saw chess stamps for the
Karpov - Fischer match that never was once on the net.
http://www.zobbel.de/stamp/fakes_02.htm
I remember reading a book review on chesscafe a while back. The book was called "a history of jewish chess players on stamps", or something like that.
The conclusion of the review was that the book would be particularly interesting to philatelists, especially those interested in jewish chess players!