Sites are already being blocked....Even though the law that allows the US Govt to do this hasn't been passed yet.....Welcome to the Corporate States of America!
Here's an Article
http://torrentfreak.com/feds-seize-130-domain-names-in-mass-crackdown-111125/
http://torrentfreak.com/dns-seizure-takes-out-megaupload-111129/
and here's the fix-as an example MegaUpload
First try using the IP address not the http...
http://174.140.154.12/
If that doesn't work, try this...
1.Click the Start Orb, then select Control Panel.
2.Click on Network and Sharing Center.
3.Click on your primary connection or Local Area Connection under Active Networks.
4.Click the Properties button.
Windows 7 may prompt you for permission to make network setting changes.
5.Highlight 'Internet Protocol Version 4' and click Properties.
6.Click the radio button 'Use the following DNS server addresses:' and type 208.67.222.222 and 208.67.220.220 in the Preferred DNS server and Alternate DNS server fields.
7.Click OK button, then the Close button, then Close again. Finally, close the Network and Sharing Center window.
At this point, we highly suggest that you flush your DNS resolver cache and web browser caches to ensure that your new configuration settings take effect.
FOR MAC: go to system prefs, click NETWORK, click your connection, click "advanced", click DNS, click +, type 8.8.8.8, click OK, click APPLY... and ENJOY!
For Linux: (another cut and paste I have NO linux experience)
Under Linux / UNIX / BSD operating system, you need to edit the /etc/resolv.conf file and add the line:
nameserver {IP-OF-THE-DNS-1}
nameserver {IP-OF-THEISP-DNS-SERVER-2}
Login as the root, enter:
# vi /etc/resolv.conf
OR
$ sudo vi /etc/resolv.conf
Modify or enter nameserver as follows:
nameserver 208.67.222.222
nameserver 208.67.220.220
Save and close the file. To test DNS configuration type any one of the following command:
$ host google.com
$ dig google.com
$ ping google.com
$ nslookup your-domain.com
Output:
google.com has address 72.14.207.99
google.com has address 64.233.187.99
google.com has address 64.233.167.99
google.com mail is handled by 10 smtp4.google.com.
google.com mail is handled by 10 smtp1.google.com.
google.com mail is handled by 10 smtp2.google.com.
google.com mail is handled by 10 smtp3.google.com.