SPN mapping - Service Principal Name

What is a SPN ? Service Principal Names http://technet.microsoft.com/en-us/library/cc961723.aspx

Service principal names are associated with the security principal (user or groups) in whose security context the service executes.SPNs are used to support mutual authentication between a client application and a service.

http://blog.powershell.no/2010/01/28/validate-spn-mappings-using-windows-powershell/

http://support.microsoft.com/kb/929650

http://briandesmond.com/blog/active-directory-spn-mappings-and-kerberos/

http://thejavamonkey.blogspot.com/2008/03/active-directory-and-kerberos-service.html

http://blogs.msdn.com/b/autz_auth_stuff/archive/2011/04/28/what-is-spn-and-why-should-you-care.aspx