Sorry for the three Keith Olbermann videos in a row, but I think that his commentary on the present concern over the issue is right on. The Supreme Court Judges have decided to support the "free speech" of non-persons (corporations), in that they can now spend any amount of money they choose on a campaign, candidate, or any advertising for them or any political issue.
People's complaints about those that govern is very often that they seem to be bought and sold by special interests. To date there have only been a couple-thousand political action committees (PACs). Now, corporations will have no reason to have them, and no oversight concerning how much money is spent promoting their 'special' political interests.
Here is the website that Rep. Alan Grayson mentions:
"When Corporations Rule the World"
David C. Korten (1995).