getmail is intended as a simple, secure, and reliable replacement for fetchmail. It retrieves email (either all messages, or only unread messages) from one or more POP3, SPDS, or IMAP4 servers (with or without SSL) for one or more email accounts, and reliably delivers into qmail-style Maildirs, mboxrd files, or through external MDAs (command deliveries) specified on a per-account basis. getmail also has excellent support for domain (multidrop) mailboxes, including delivering messages to different users or destinations based on the envelope recipient address.
Wallal is a standalone LDAP-to-Web gateway. It allows you to search, add to, modify, and delete from an LDAP database. It can format entries and validate them upon submission, and the entries displayed are fully configurable. It was designed with a "personal" LDAP server in mind (one that is used primarily as a phonebook). However, it should be reasonably easy to modify it to do more complex operations on a directory.
MIR (mobile IMAP reader) is a WAP frontend for reading email from various IMAP accounts. You can browse and read email messages stored in different IMAP mail folders. It is developed with efficiency in mind, and optimised to present all information on a mobile phone in a compact form without any overhead.
mailbox_date_trimmer is a tool for mailing list archives that corrects messages' date headers if they are incorrect. Incorrect means that a message following another has a time difference bigger than one month, usually when the owner of the message had his clock misconfigured. After fixing the archive, running Hypermail over the mailbox will create correct discussion threads.
SpamGAME is an email classifier based on the GA.M.E. (GAussian Mono-dimensional Environment) algorithm for text categorization. It takes an email message on standard input, does a statistical check against lists of "good" and "bad" words found in the past emails received by the user, and returns the email message adding the email header 'X-Spam: yes|no'. In addition, as prefiltering methods, it uses whitelist/blacklist address filtering.