ITIL, the IT Infrastructure Library, was developed by the UK Office of Government Commerce and is currently gaining wide acceptance as an approach to managing IT Services. From the Official ITIL Website (http://www.ogc.gov.uk/index.asp?id=2261):
ITIL provides a cohesive set of best practice, drawn from the public and private sectors internationally. It is supported by a comprehensive qualifications scheme, accredited training organisations, and implementation and assessment tools.
Some background to the structure of ITIL practice is covered in the ITIL Structure paper.