Found this randomly. Here's what you do:

1. Click this link
2. Pick a football team (click on one of the helmets)
3. Campbell's will donate one can of soup on behalf of the NFL team you selected

There's nothing more to it, they don't ask for your name, they don't ask for an email address, there's no sign-up - nothing. Just go to their site and pick a team. Their goal is to donate 5,000,000 cans, right now they're at 4,331,024.