Client daemon to move mail from POP and IMAP to your local computer
Fetchmail is a mail retrieval daemon that can download messages from POP3, IMAP, ODMR and ETRN-based stores, with SSL/TLS security including certificate verification, and pass downloaded mail to a local SMTP or LMTP server, or a message delivery agent such as maildrop.
gavamail is a POP3/IMAP server implemented in JAVA for reading your gmail e-mail with your favorite mail client. Currently only POP3 is implemented but I hope to implement IMAP too. Libraries provided by the g4j and libgmail projects are used.
Active Spam Killer for Windows (AfW) is a challenge/response spam filtering system for the Windows platform. Based on ASK for Linux by Marco Paganini, this project adds a POP3 client/server wrapper and web administration, as well as Windows compatibility