The International Virtual Observatory Alliance (IVOA) is three things - a standards body, a discussion forum, and a mechanism for sharing best practice. It was formed in 2002 and now comprises 17 VO projects from Armenia, Australia, Brazil, Canada, China, Europe, France, Germany, Hungary, India, Italy, Japan, Korea, Russia, Spain, the United Kingdom, and the United States.

The work of the IVOA focuses on the development of standards, and uses methods modelled on those of the W3C. It uses Working Groups centred around key technical standards. These have wiki-based and email-based discussions as well as bin-annual international meetings. Recommendations are ultimately endorsed by the Virtual Observatory Working Group of Commission 5 (Astronomical Data) of the International Astronomical Union. The IVOA also has Interest Groups that discuss experiences using VO technologies and provide feedback to the Working Groups.

The IVOA web page is here. It includes guides to the VO for both astronomers and developers, and a complete list of standards developed so far