RetrieveUserData is a plugin for the webmailer Squirrelmail. It retrieves a user's name and e-mail address from a configurable source like LDAP or MySQL. Your users don't need to configure Squirrelmail before writing their first mail.
Please send messages to Ralf Kraudelt (kraude(at)users.sourceforge.net) and have a look at http://sourceforge.net/projects/retruserdata/.