This Microsoft KB article lists 3 ways to grant non-admin users the rights to manage services on a windows machine.
Method 1: Grant rights using Group Policy
Method 2: Grant rights using Security templates
Method 3: Grant rights using Subinacl.exe
The easiest and fastest method? Method 3 using subinacl.
SUBINACL /SERVICE \\MachineName\ServiceName /GRANT=[DomainName\]UserName[=Access]
[Source: How to grant users rights to manage services in Windows 2000]