Speaking of PACs, I found this interesting. You can see that the unions predictably have given mostly to democrats, but look at some of the large companies listed there. comcast, AT&T, UPS, Boeing etc. I'm not even going to say which side they gave most of their money to, you can guess I'm sure.
http://www.opensecrets.org/pacs/toppacs.php
http://www.opensecrets.org/pacs/toppacs.php