I want to test or install Kerberoes for authentication.
Is it a part of AD DS or a stand alone application which i can install on window server 2008
Do i need anything else to make it working
You don't need to do anything special besides install AD to get kerberos. Essentially:
Kerberos + LDAP + MS Extentions to LDAP = MS AD
Basically what you have there is the following:
Kerberos does the AUTHENTICATION in an active directory network