MailDrop - maildrop is a Mail delivery agent used by the Courier Mail Server. The maildrop MDA also includes filtering functionality. maildrop receives mail via stdin and delivers in both Maildir and mbox formats.
Guerrilla Mail - Guerrilla Mail is a web-based app that provides a disposable and anonymous email address. Users of the service are not required to set up an account in order to send or receive emails.
Faruno - A unique email address within one inbox
10 Minute Mail - Temporary disposable e-mail service to beat spam. Avoid spam with a free secure e-mail address.
AnonAddy - Create unlimited aliases for free. Protect your email from spam using disposable addresses. Encrypt forwarded emails with PGP encryption using this service.
Mailinator - Any Inbox. Any Time.