Most employers today are looking for System Administrators that know business administration as well. A good start for IT management is the Information Technology Infrastructure Library (ITIL), which was created by the United Kingdom's Central Computer and Telecommunications Agency (CCTA). ITIL represents a drastically different approach to IT by framing all activity under two broad umbrellas named Service Support and Service Delivery respectively. By focusing on the critical business processes and disciplines needed to deliver services around IT, the ITIL provides a maturity path for IT that is not based on technology. This accessibility allows senior executives to both sponsor and shepherd IT quality improvement efforts. The ITIL has become the most widely accepted approach to IT service management.
ITIL provides a comprehensive, consistent volume of best practices drawn from the collective experience and wisdom of thousands of IT practitioners around the world. By defining IT quality as the level of alignment between the actual services delivered and the actual needs of the business the library serves as a common point of engagement for IT and the other business units.
Under this scheme System Administration can be thought of as consisting of these sub-areas:
The companion website for the ITIL is www.best-management-practice.com. Check out their IT service management resources, including some Introductory overview of ITIL paper (PDF).