TWIG is a Web-based groupware suite written in PHP, compatible with both
PHP3 and PHP4. Its features include IMAP and POP3 email, Usenet newsgroups,
contact management, scheduling, shared notes and bookmarks, a todo list,
and meeting announcements. Any piece of information can be shared with others
via group oriented access controls. By using only plain HTML, it is a simple,
cross-platform, fast and browser-independent way to access or share almost
any kind of information, without the complexity or costs of other
intranet/groupware packages. It is fully internationalized, with 22
translations. 

WWW: http://twig.screwdriver.net/