How to freeze your credit after a data breach

Yesterday, Equifax announced that hackers stole half of the US population's Social Security numbers in what will likely end up being one of the worst data breaches to ever affect the country. If you're one of the victims, you might consider freezing your credit. Here's information on how to do that, and what it entails.
How do I know if my data was stolen from Equifax?
Equifax built a website for the data breach where you can type in your name and the last six digits of your Social Security numb