In addition to the documentary already mentioned (Food Inc) check out "King Corn", "The Future of Food" and "The World According to Monsanto" which can be watched free online:
Documentary Film Video Documentary About Monsanto
Monsanto's GMO corn cross-pollinates into corn-fields that aren't using Monsanto's product, the owner's of these cross-pollinated corn fields are then sued out of business by Monsanto whom employs a team of people to go onto farmers' property and test for any evidence of their GMO corn.
The GMO corn can't even be eaten in it's freshly grown state, it is produced solely to make corn syrup which is an ingredient in just about every product on your supermarket's shelf.
We have so much corn that without the government subsidy to farmers, it costs more to grow corn than it's worth. Which leads to needing more uses for the corn than food; enter ethanol (another subject worthy of it's own thread).
Monsanto's effect on the world's food supply and health is mind-boggling and frightening.
Monsanto's Government Ties
Clarence Thomas who was a Monsanto attorney, the U.S. Secretary of Agriculture (Anne Veneman) was on the Board of Directors of Monsanto's Calgene Corporation, the two congressmen receiving the most donations from Monsanto during that election cycle were Larry Combest (Chairman of the House Agricultural Committee) and Attorney General John Ashcroft. (Source: Dairy Education Board).
Some of the people that work for Monsanto go on to careers in the Federal govt (like the FDA) where they can continue working for Monsanto.
From a Monsanto in-house newsletter in 2000:
"Agricultural biotechnology will find a supporter occupying the White House next year, regardless of which candidate wins the election in November"