Please sign cradl's petition, "a place for ordinary Americans to register their concern and discontent about sacrificing freedom in the name of freedom". And please spread the word!
cradl was founded by Jesselyn Radack, formerly an internal-ethics advisor in the Department of Justice. Until the administration didn't like her call regarding whether the FBI could question John Walker Lindh without his attorney being present, and she didn't shut up on the subject. There are several articles about her linked from the petition page.
Thanks to riba_rambles for the link!