"TorK is a frontend that allows you to access the anonymous Tor
network from the KDE desktop. It gives you one-click access to
anonymous surfing, e-mail, and chat. Operating System: Linux,
"A type III anonymous remailer, Mixminion offers both client and
server code for sending and receiving email that is difficult to
trace. Note that this is still a work in progress aimed primarily
at developers or the technically knowledgeable. Operating System:
Windows, Unix, OS X."