Please add additional links to useful software below
The Astrogrid Project distributes software modules for deploying a registry. Click on the "Registry" link in the left-hand navigation bar on their software page for the latest releases.
The US NVO Project distribute several registry packages of interest to providers which are accessable via their registry software page. This includes...
The ServiceValidation page is for tracking coordinated IVOA efforts to create and maintain service validaters, tools that check the compliance of an instance of a service to its standard.