The most progressive use of information design, the structuring of data using the principles of visual communication, in government can be found on the web page for the Recovery Act.
The goal of information design is to clearly represent data in such a way that it is easily understood by the viewer.
The guru of this field of design is Edward Tufte, who was recently to the independent panel that advises the Recovery Accountability and Transparency Board.
Audio:What is Information Design
Recovery Act Website
Article: Profile on Edward Tufte