The ISO/IEC 20000, the international standard itself and the ITIL which is a British version, are both documents, best practices as well as standards-considered in service management. The latter, was called the BS 15000, was then fast-tracked to become ISO/IEC 20000, now the first international standard in service management, as described in the Office of Government Commerce Web site.
Information technology service management, ISO 20000 family
Information technology infrastructure library (ITIL)