There's a huge campaign afoot to send a gigantic amount of nuts to CBS, in honor of the "Nuts" story told in the series finale. As of this writing there are almost 17 THOUSAND pounds of nuts being sent to CBS!
There's also a fundraiser underway to place a full page ad in Variety.
There's a "Save Jericho" section over at the official site, where many things are being discussed, including boycotting CBS. I'm already doing that as Jericho was the only show I watched on the network.
And then there's lots of news coverage on the cancellation and attempted revival of the show at the following sites: The New York Times, Defamer, CNN Money, Entertainment Weekly, Pittsburgh Post-Gazette, and The Los Angeles Times.
I don't know if this will all do any good... there was a hell of a movement to save Star Trek: Enterprise, and unfortunately that went nowhere. Does my heart good to see this, though!