How do I find out if my email and password have been leaked?

So, I got this in my morning email:
At Amazon we take your security and privacy very seriously. As part of our routine monitoring, we discovered a list of email address and password sets posted online. While the list was not Amazon-related, we know that many customers reuse their passwords on several websites. We believe your email address and password set was on that list. So we have taken the precaution of resetting your Amazon.com password. We apologize for any inconvenience this has caused but felt that it was necessary to help protect you and your Amazon account.

So, aside from changing my Amazon password, how can I find out if I was on this list?