I first heard about this from a system message on the Stack Overflow site. The post Protect intellectual property – but not like this explains their position (in particular, SOPA vs. DMCA) and has a lot of good links to more information.
SOPA-Rope-a-dope has a well written explanation of DNS blocking and DNSSEC.
This bill is a really bad idea. A lot of people in the know agree: An Open Letter From Internet Engineers to the U.S. Congress.
Congress to Resume SOPA Hearings Next Week (Wednesday 12/21) so it's not too late to help stop this bill. If you're like me and have always wondered why people contact their Congressperson, now we finally have a good reason to do so. Go to Stop American Censorship and let your voice be heard.
From RWW Cartoon: SOPA Opera:
UPDATE (12/23/11): Bill that could 'break the Internet' delayed until 2012. Also see: What You Need to Know About SOPA in 2012