Get the Most Out of Alpine and Pine
Alpine is powerful console email program that makes you use email productively with automation aplenty and nary a distraction. (Windows, Mac, Linux)
Pine is an easy to use and rock solid email client with great flexibility on Unix and with IMAP accounts. (Windows, Mac, Linux)
All About Pine
Nancy McGough's fantastic page on all things Pine is a bit difficult to navigate, but reading it from A to Z is worth it anyway.
Patches for Pine
Extend the functionality of your copy of Pine with useful features, correct bugs, and have fun experimenting with Pine and making it an even better email client.
PGP4pine uses Pine's ability to pass incoming and outgoing mail through external filters to implement some support for PGP message encryption and signing in Pine.
The Pine FAQ from the University of Washington covers many questions about using, configuring and wrestling with Pine.