Grey literature exists outside of and is uncontrolled by the usual academic and commercial publishers. It includes conference proceedings, occasional and working papers, policy papers and briefs, hearings, reports, and more.
CGS Policy Archive-- collects and archives public policy research publications from US think tanks.
NIRA World Directory of Think Tanks-- indexed by country with descriptions, contact information, and links to organizations' website
WWW Virtual Library: Research Institutes-- list of think tank-related links and resources maintained by Wayne Selcher at Elizabethtown College
Public Policy Institutes-- a Yahoo directory of important international think tanks with links to organizations' websites.
For every day Congress is in session, Capitol Words visualizes the most frequently used words in the Congressional Record, giving you an at-a-glance view of which issues lawmakers address on a daily, weekly, monthly and yearly basis.