VistA

HardHats.org -- is an online community to promote VistA and to help develops and users implement the software. It is currently the definitive place for VistA resources.

WorldVistA & OpenVistA -- according to the their web site, "WorldVistA has formed to help make healthcare information technology more affordable and more widely available both within the United States and internationally. WorldVistA extends and improves VistA for use outside its original setting through such activities as developing packages for pediatrics, obstetrics, and other hospital services not used in veterans' hospitals. WorldVistA also helps those who choose to adopt VistA successfully master, install, and maintain the software."

Medsphere -- is a corporation that provides consultative and implementation services for OpenVistA.