Public Frontend Plugin
This plugin enables "Public Frontend" functionality. When you enable the Public Frontend
unregistered users can send PMs to registered users.

RSS Message Feed Plugin with iGoogle Gadget
This plugin publishes your inbox using a RSS feed. So you can display PMs in your favorite
RSS reader or on your personalized iGoogle page. There is also a iGoogle gadget available which
shows the content of the inbox (you can use any RSS gadget you like).

Message Report Control Center
This plugin enables the "Report message" feature, so users can report messages (e.g. SPAM)
to the Admin. In the backend the Admin can check all reported messages and take appropriate
actions.

File attachments Center
This plugin enables "File attachments" in uddeIM, so users can send files to each other.
It is highly configurable, so admins can specify the allowed attachment size and what groups
are allowed to send file attachments.

You will find more information about these plugins in the FAQ section 3.