Difference between ES and Open SUSE

I am new to SUSE. I want to know the difference between various versions of SUSE 10.0.

  1. SUSE Enterprise Server(ES?) 10.0
  2. SUSE Enterprise Desktop 10.0
  3. Open SUSE 10.0

How each version is differ from other and also is there any specific usage of a version?

I suppose you mean version 11 because version 10 is outdated now. Here is a brief explanation on wikipedia with a comparison between the 3:
SUSE Linux distributions - Wikipedia, the free encyclopedia