1. Install this Firefox add-on by clicking this link and following the instructions: http://bit.ly/dnCc8I
2. Copy the following into a .txt file and save it somewhere on your computer. The easiest way to do this is Start, All Programs, Accessories, Notepad. Come back to your browser, then select the following text with your mouse, and pull down the Edit menu and pick Copy. Then go back to Notepad, and pull down Notepad's Edit menu and pick Paste.
This puts this list in Notepad. Now pick File, Save in Notepad, and save the file in My Documents with the file name SummersEve.txt.
3. Goto Tools > Add-ons in your copy of FireFox and click the Preferences button for the BlockSite add-on.
4. Make sure the blacklist radio button is selected and use the import button to import your list from My Documents\SummersEve.txt.
5. Enable BlockSite, warning messages, and link removal.
Now, you won't be able to unintentionally visit one of the Evil Empire's websites. Obviously, you can disable the Add-On, or change the list if you need to. This is primarily to protect yourself from the infamy of putting even a fraction of a penny in the pocket of these creeps.
UPDATE: From the comments here:
And from a comment over at Snowflakes in Hell:
There is an extension for chrome called 'SiteBlock' that seems to do the same thing for that browser.
If you want to join in on the Stevens Media boycott with Safari, GlimmerBlocker is an open source proxy based solution for Mac OS X (10.5+).