As Philipp noted the other day, Google has formed a political action committee. This ResourceShelf post has a bunch of links.
http://www.resourceshelf.com/2006/09/17/search-briefs-google-registers-syndicated-related-domains/

A) The primary documents Google has filed (also can be used for monitoring)

B) Links to Documents (who gave what etc) from Yahoo, Microsoft, and IAC. They've had PACS for years.

C) A link to a CRS report about campaign finance in the U.S.

D) A Direct link to this database
http://www.fecinfo.com/cgi-win/indexhtml.exe?MBF=EMP

It allows you to search for contributions to individual candidates or PACS by specific people from specific companies or organizations. Database goes back to 1980.

So far in the 2006 election cycle a search for :
Google listed as employer turns up 142 records. Yahoo, 67 records. Microsoft, 1533. IAC, 68. Note: You’ll find both contributions to specific candidates and PACs. In some cases, a person could have multiple entries.

Finally, not unexpected, Google has just registered several political action committee related domain names.

+ google-net-pac.com/net/org
+ google-netpac.com/net/org
+ googlenetpac.com/net/org
+ googlenetpack.com/net/org
+ netpac-google.com/net/org
+ netpacgoogle.com/net/org