The Center for Public Integrity has an outstanding record for nonpartisan investigative reporting.
They're working on tools which would allow anyone to see who's paying politicians for favors. Their first database to that effect is lobbywatch, which tracks money paid for lobbying activities (the money spent to directly influence the actions of the federal government), not money paid to politicians. You can look up companies, lobby firms, individual lobbyists and the issues they lobby on. The next step is to combine LobbyWatch with the money paid to politicians and simultaneously track the legislative activity of those politicians.
Right now, CPI is analyzing more than 25,000 paper records on privately funded travel by members of Congress and their staffers (the kind of travel at the heart of the Abramoff scandal).
People, this is a really big deal, any of you can perform serious investigation relating to corruption.