The Center for Responsive Politics has a website called: http://www.opensecrets.org/
They're a non-profit org and far as I have found so far are legit.
Their website is rather . . . well. Awesome. For instance they have a section under "Influence and Lobbying" called "Revolving Door" which shows which lobbyists have become politicians and also where politicians have ended up working after being in government (often ending up as lobbyists).
Information covers and can be sorted by a wide range of criteria: by elections, type of government post (president, senate, congress, etc), lobbying firms, interest groups, organizations, agencies, congressional committees, etc.
An example of some more of the information they have: http://www.opensecrets.org/news/reports/supercommittees.php
That link shows the money backing of each member of the Joint Select Committee on Deficit Reduction, often called the Super Committee, that was formed by the Budget Control Act which Obama signed into law in August. Can see the totals on the link provided for everyone, or click on a committee member's name and get a further break down, example this is Jeb Hensarling (Republican co-chair fo the committee) showing the top 20 contributions by industry: http://www.opensecrets.org/politicians/industries.php?cycle=2012&cid=N00...
Anyway. A very good repository of information if anyone wants or needs to look up some figures for money in politics.