Just wanted to add this site. The Government IT Wiki. I found it interesting because it's attempting to track all types of information technology and computer spending by the government. (Mostly U.S. focused at the moment, but it does have some international data.

Includes individual agency details on computers, hardware, software, applications, network equipment, upgrade paths, preferences, procurement cycles and more. Also covers security issues and presidential initiatives such as management agendas and OMB or CIO architecture requirements.

http://www.govitwiki.com