As mandated by the Obama administration, each agency had to submit a sustainability plan on the Executive Order 13514. Each agencies sustainability plans can be accessed via the White House link.
The U.S. General Services Administration (GSA) has their own site on the initiatives that GSA is doing in regards to green building, green procurement, telework, waste management, sustainable travel and alternative fuel vehicles. GSA also commissioned a Sustainable Facilities tool that is free that helps to identify and prioritize cost effective green building strategies, both for federal and private buildings.
The U.S. Environmental Protection Agency has a page of resources dedicated for federal agencies and promoting sustainability and the environment.
The Canadian government also has a terrific site on initiatives, plans, resources, publications on their national sustainability initiatives in Canada.