Is there an easy way to find out which companies, trade organizations
or pacs give money to a specific politician?  If yes, can you tell me
how to do it?

Hello infopros,

There are at least three sites on which you can look up contributions
to candidates for federal offices, either by candidate or by
contributor:

"Disclosure Data Search"
Federal Election Commission
http://www.fec.gov/finance/disclosure/disclosure_data_search.shtml

Opensecrets.org [The Center for Responsive Politics]
http://www.opensecrets.org/

Political Money Line
http://www.politicalmoneyline.com/

I would suggest browsing each of these sites for a few minutes, and
trying a few sample searches, in order to determine which you find
easiest to use or most informative.  If you need clarification on how
to conduct a particular search, please let me know.

As for candidates for state office, you should try:

Follow the Money [The Institute on Money in State Politics]
http://www.followthemoney.org/

The key to using the lookup on that site is to select the state and
year (under "State-at-a-Glance") before entering the contributor or
candidate name.

Here too, if you need clarification, please let me know.

- justaskscott


Search strategy --

Searched on Google for:

campaign contributions

I also searched for various combinations of domain names (e.g.,
opensecrets) from useful sites that appeared in the initial search.

On the money!!