Pegasus Mail is a free e-mail client that can be used by single or multiple users on individual computers or local area networks. It is an extremely powerful, feature-filled client that sometimes gets overlooked in the market.
Some of the basic features include:
Mail filtering
Support for multiple identities
Support for all Internet mail protocols, including SMTP, POP3, IMAP4, LDAP and PH.
Along with the basics comes the same kind of support that is found in the better-known e-mailers, including Spell check with UK and U.S. English dictionaries, a powerful encryption interface with support from PGP, and support for multiple POP3 and IMAP mailboxes.