Anonymous Email: https://mixmaster.autistici.org/cgi-bin/mixemail-user.cgi
Anonymous Usenet Posting: https://mixmaster.autistici.org/cgi-bin/mixnews-user.cgi
The Mixmaster remailers are a series of anonymous remailers that do not use PGP, but rather they have their own strong encryption system used to encrypt the messages sent back and forth. This anonymous email format is called "mixmaster" because the remailer does just that: it mixes up the order in which it sends its encrypted email, so that the first email received is not necessarily the first email it sends out. This makes it harder to track the path of a message back through the remailer network based upon its time of receipt and the time the remailer sends its email packets out to the next remailer.
The Paranoia Mixmaster remailer has an easy-to-use Web-based interface that allows anyone to send their own encrypted emails (or Usenet postings) from the Web. This is about as simple as you can get, if you want to send anonymous email and remain hidden.