Go to wikipedia. No, really. They've got a javascript set up to take you to info on it. Many sites chose to black out in protest, as it basically censors parts of sites that are involved in file sharing or even link sharing. But 3 sponsors backed out on the bill just today from the huge amount of protest against it, so I don't see it going through at all (not that it would have anyway).
Also, as a side note, an interesting thing about it is that the sponsors of the bill are companies like cnet, who actually developed the file sharing software. It's pretty much just a money ploy to sue people for using the products that they distributed, making their companies money off of their own illegality. Quite some interesting implications - you can learn a lot about politics just from this bill, as well as how companies work with the government to suit their own needs.
thank you!