Track how much cash any given industry has given to federal political campaigns over the last decade. See how much the Congressman you're lobbying has received from the other side. Or check the level of contributions coming out of your zip code. Opensecrets.org even provides a handy rundown of legislation in the news and shows which special interests have been especially interested.
For more Web resources, check out the City Limits Research Center, updated every Tuesday and Friday, at http://www.citylimits.org/content/research/research_view.cfm.