nget is a commandline NNTP file grabber. It automatically pieces together multipart postings for easy retrieval, even substituting parts from multiple servers and newsgroups. It handles disconnects gracefully, resuming after the last part successfully downloaded, and caching of header data for quick access. It automatically downloads only as many par/par2 files as needed.
nmh (new MH) is a powerful electronic mail handling system. It was originally based on version 6.8.3 of the MH message system developed by the RAND Corporation and the University of California. It is intended to be a (mostly) compatible drop-in replacement for MH. nmh consists of a collection of fairly simple single-purpose programs to send, receive, save, retrieve, and manipulate e-mail messages. Since nmh is a suite rather than a single monolithic program, you may freely intersperse nmh commands with other commands at your shell prompt, or write custom scripts which use these commands in flexible ways.
NOCC is a simple and fast Web-based e-mail reader which can handle POP3, SMTP, and IMAP servers. It is written with PHP5, and uses sessions, has low requirements (no database, frames), and is easy to install. It also features multi-language support, MIME attachment decoding/encoding, and the ability to display HTML messages.
NS WebMail offers standard mail functions for POP3 inbox management. Mail is sent using SMTP protocol. It has been designed to be light and simple, to avoid having to use heavy IMAP or SQL servers, and it has full MIME support for incoming and outgoing mail. It is Perl-strict and mod_perl-compliant, and has security using HTTP authentication or cookies. LDAP connectors are also available (as optional plug-ins) for authentication and read-only address book. Two interfaces are available (with and without frames). It is able to recognize tags from spam detection software (Spamassassin is supported out of the box).