Aileron is an email client written for the WindowMaker window manager.
It is based on the WINGs widget library.  The philosophy behind Aileron
is to be as similar to NeXTSTEP's Mail.app as possible, right down to
the menu keybindings.  Aileron will play nice with pine, elm, or whatever
other mbox mail reader you use.  There will be a few deviations from the
original Mail.app, most of which the average WindowMaker user will
appreciate.

WWW: http://ucsu.colorado.edu/~nwanua/Aileron/