Updated: 12/29/2005
EmailAnon
Blackbox mail , 665kb
Anonymous email client. [Report a dead link]
http://homepage.tinet.ie/~blackbox/

Jack B Nymble
Jack B. Nymble v1.3 is a full email application, native to Windows95 and fully compatible with WindowsNT. This freeware package facilitates the use of anonymous remailers, including Cypherpunk (Type I), Mixmaster (Type II), and pseudonymous remailers (newnym accounts). Jack B. Nymble is capable of creating anonymous and nym messages which include unlimited control of headers, support for unlimited attachments in MIME, UUEncode, and PGP, full support for newsgroup posting via mail2news gateways, and automatic PGP encryption and signing of messages.

Requires: PGP, Mixmaster (if sending via Mixmaster remailers). [Report a dead link]
http://www.skuz.net/potatoware/jbn/about.html