I don't usually bother with Internet petitions, so to speak, but I went ahead and did this one: Take the ACLU's "Refuse to Surrender Your Freedom" Pledge

It's mainly a membership drive. I think folks who care about civil liberties could do worse than join the ACLU and/or sign up for their action alert newsletters. They do some annoying things by overfocusing on some civil liberties and ignoring others, but they also do some good things, and they seem not to focus strictly on white middle-class concerns.