The stations that carried him, fired him because his gaffe cost them advertisers. It was strictly a business decision. In the same vein, please feel free to boycott the companies who dropped their adds because of Imus, should you wish to support him. If enough people do this, he will undoubtedly be rehired. I couldn't be bothered, personally. I refuse to go out of my way to support public stupidity.
That said, PLEASE, let's NOT clean up the airways. Between the authoritarian right ("We know what god wants you to do/think/say/listen to/watch") and the overly helpful left ("But what about the CHILDREN??!! Think of what they could see or hear), the airways would be too bland to bother with. It's about time to tell Mrs. Grundy to piss off.
my 0.02...