WMBiff is an WindowMaker dock applet that displays the number of read and unread messages in up to five mailboxes.
You can define actions to execute on new mail arrival (for example, play a sound file), [auto]fetchmail from a remote server or execute your mail reader with a mouse click. WMBiff also supports polling the output of shell commands, so you can extend its functionality easily via shell scripts.
At this moment, wmbiff supports unix-style, maildir, pop3, APOP, IMAP and IMAPS mailboxes, as well as Licq and GnomeICU history files.
For more information, have a look at: