MAK - TclMilter is a package for Tcl (written in C) that implements an interface to SendMail's Milter [L1 ] (Mail Filter) API [L2 ] for developing custom scripted message rewriting and spam filtering processes. A thread-enabled Tcl build is required due to Milter's threading requirements. However, you can only run, configure, or register callbacks for a milter from the first thread/interpreter the package is loaded into. If you need to be able to stop the milter from within Tcl, you can load the package in another thread to do so. Only the "milter stop" command will function in secondary threads. TclMilter is provided under the GNU General Public License (GPL).
http://www.muonics.com/FreeStuff/TclMilter/
(26 Jun 2005) - Documentation is available as of version 1.0.