Turning off a few big Websites is a nice gesture. I'm sure the operators of Wikipedia, Reddit and the other sites that are going dark are proud of themselves for making the statement, and are probably patting themselves on the back, thinking they struck a blow for an open Internet. They're kidding themselves. Congress doesn't care.
Members of Congress mostly care about one thing, and that's getting re-elected. This being an election year, they care about it more than they will next year. The only way to fight bills like the Stop Online Piracy Act (SOPA) is to appeal to members of Congress in a way that makes them worry about getting re-elected.
The reason members of Congress pile on to bills such as SOPA and the PROTECTIP Act (PIPA) is that their party leadership, along with some big donors, tells them they should do this because it will enhance their chances in November. Toeing the party line will help get party and Political Action Committee (PAC) support. Courting big donors will ensure big donations to their private PACs. As you've probably noticed, movie studios and recording companies have lots of money that they donate to PACs. Thus, members of Congress tend to do what they say, unless something convinces them to do otherwise.
Your job, assuming you care about an open, operational Internet is to give them a reason to do otherwise. This means you need to get their attention in a way that works, and you need to give them a reason to listen to what you have to say.
When I was researching my book, "Politics on the Nets" one of the things I learned is that actions that take place on the Internet or by email rarely affect legislation. Some time has passed since then, but the Internet hasn't gained much in its power to influence Congress. So, here are the steps you need to take if you really want to get something done in Congress.
1. Write your representative in Congress and your two U.S. senators a letter expressing your ideas calmly and without technical jargon, including Internet slang. Yes, I said write a letter. This does not mean an email and it doesn't mean a blog entry. While some politicians really do read their own email, the most of them delegate that to a junior staffer who decides what email, if any, gets sent along to the legislator. That means your letter must be printed on paper and signed, along with your physical snail-mail address so that they know that you're a constituent.