ldap-abook is an LDAP-based addressbook application, intended for users wishing to maintain a centralized server based addressbook. It provides a schema for an LDAP directory, a Perl library module, and a CGI script. The Web interface is used to view, add, modify, and delete entries. Any LDAP-aware email client (eg. Netscape Messenger, Microsoft Outlook, Lotus Notes, etc.) can be configured to look up email addresses on the LDAP server. The package also includes a Perl script which can be used to dump the directory onto a PalmOS device.
XFMail is an X11 application for receiving electronic mail. It implements most of its email functionality internally so that it does not depend on a lot of extra packages. It supports POP3, MBOX, IMAP4, sendmail, and SMTP. It has built-in support for interfacing with PGP, GPG, ispell/aspell, faces, LDAP, and esound. It runs on most Unix variants.
Twiggi Web Based Groupware is a Web based groupware application, written in PHP4, using MySQL as its database engine. It was originally based on the excellent TWIG project. With many on-going enhancements, it is similar to Microsoft Outlook, and features the following modules: twiggi today, Mail, Contacts, Notes, ToDo, Bookmarks, and extensive online help (available in English and German). Twiggi has full language support for German, Dutch, Italian, and English.
eXtended Account Management System (XAMS) allows Administration of Unix, Web, FTP, DNS, and email accounts to manage a provider's typical userbase. Especially focusing on email account management, it enables you to easily create accounts, set aliases, and delegate domain administration to 2nd party resellers or customers. It uses PHP with MySQL or PostgreSQL as a backend, and is therefore able to manage tons of email accounts independently from your Unix/Linux accounts. Exim for SMTP and Courier for POP/IMAP are fully supported, but postfix, Cyrus, and qmail can be used too.
Csv2vcard is a program for converting CSV (comma separated values, as exported by software such as MS Outlook) files containing contact information to the industry standard vcard format, which can be imported by most mailers and PIM software (optimized for Evolution). It's based on a Perl script by Michael MacDonald of Ximian. Csv2vcard can be used to convert any CSV format, not just the English Outlook output.