[Plugin: 404-to-start] 404

It works for me! 3.0.4 multisite

This works great for my blog. I had built some wordpress sites on various domains related to my blog, but later decided to just point the domains to my main domain. Since a bunch of pages were already indexed from the sites sites that I got rid of, people were getting 404s when they clicked on those links. This plugin solved the problem.