I apologize for the incomplete information that I provided. The service is set to auto on NT and W2k domain controllers only. If it is just a member server, it is set to Manual.
The purpose of the Locator service is:
Prior to Windows 2000, Microsoft Locator did not provide persistent name service entries. All entries in the name service were stored in a memory cache on the server program's host computer. The locator used a broadcast mechanism to discover the location of servers as requested by clients. Whenever the host system shut down, all name service entries were lost.
Beginning with the release of Windows 2000, Microsoft Locator now supports persistent name service entries.
see http://msdn.microsoft.com/library/default.asp?url=/library/en-us/rpc/rpc/using_microsoft_locator.asp
