Is there a way to find what accounts can execute xp_cmdshell?

I'd like to find out what users on a SQL Server sys开发者_开发百科tem can execute xp_cmdshell. Is there a query that will do this?

I'd like to know how to do it for SQL Server 2000 - 2008

Googling "xp_cmdshell":

When first enabled, xp_cmdshell requires CONTROL SERVER
permission to execute and the Windows process created by
xp_cmdshell has the same security context as the SQL Server 
service account.

http://msdn.microsoft.com/en-us/library/ms175046.aspx