OpenSecrets.org Center for Responsive Politics - Interest Groups Capsule summaries of organizations and their spending from a research group tracking money in U.S. politics and its effect on elections and public policy. Look for the directories on the left side of the page for Interest Groups by Sector and by Alphabetical Listing by Industries. Use the search box on the right if you know the name of the special interest group.
SourceWatch.org Front Groups The Center for Media and Democracy a "collaborative resource [think Wikipedia] for citizens and journalists looking for documented information about the corporations, industries, and people trying to influence public policy and public opinion." Front groups are described here as "an organization that purports to represent one agenda while in reality it serves some other interest whose sponsorship is hidden or rarely mentioned -- typically, a corporate or government sponsor." Scroll down to find an alphabetical list of Example groups after the overview of front groups. A link with a name of a group leads to a description of the group.