You should check out this post by Sente if you haven't already.  If you care at all about City of Heroes/ Villians he gives a good rundown of efforts currently underway to keep CoX alive.  Though I am skeptical that online petitions generally do much good, there is one for CoH and signing it is an easy way to show your support for the game.  Plus, reading through the comments to the petition and seeing just how much passion so many players have for CoX is heart warming.