While Google won't be blacking out, which would have really put the House and Senate on notice, it won't. Instead of that, it will post a link on its home page showing its opposition and protest to the SOPA, and the PIPA. It shall be noted that the normal, multi-colored logo of Google will not change.
And look for the next discussion article: What will you do to find information when Wikipedia is blacked out. That article will be tagged as discussion, so you can't miss it.
Update: The Google logo has not changed, but it is now covered up in black with the lowercase "g" sticking out a little bit. Take a look below to see it for yourself.