Please check the archives. This has been brought up before.
http://www.cbc.ca/technology/story/2007/01/11/wikileaks-whistle.html
quoting from the article:
> Wikileaks uses an anonymous protocol known as The Onion Router, or > Tor, which encodes routing information in a set of encrypted layers > to hide its path. One expert told the New Scientist magazine that the > encryption the site uses may not be enough to protect whistleblowers.
-James
-- James Muir http://www.scs.carleton.ca/~jamuir