"1. TorK
"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, Unix.
"2. Mixminion
"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."
