If you are unfamiliar with what this is all about, please read this article, this article and this article. For everyone that doesn't really care, I get it. But if you do, here is how I did it:
Find your Representative here: http://www.contactingthecongress.org
Write them a message via their e-mail. Here is what I wrote.
The following information has been submitted:
Name: Mr. Adam E Smith
Message Text: Good morning Congressmen Klein, I won't waste much of your time but I felt obligated to stress how important it is that you oppose anything that violates Net Neutrality. Please speak openly and vote in such a way as to protect the tens of millions of Internet users - and uphold the 1st Amendment of the Constitution. If you have any amount of influence with the FCC can you please exercise it in order to avoid what could potentially be extremely harmful to the public at large. Thank you for your time now and in the future.
It may not do anything - highly likely, but it takes 5 minutes at best and who knows, maybe formally complaining before it happens will be more productive than bitching about it on after.