I've made a slight modification in the handling of the subject tagging. The new version (DistList v1.2b5 & DistList 2007 v2.1b4) allows to switch on and off the subject tagging on the distribution groups individually.

Download links:

DistList (Exchange 2003 version)

DistList 2007 (Exchange 2007 version)

Documentation

Source code

Two years ago I was writing an Exchange 2003 SMTP Sink and an Exchange 2007 Transport Agent what able to switch an Exchange distribution list to a mailing list. This software was never published before because I'd no time to clean up the code and write proper documentation to it.

Now I'd time to finish this work so here thay are:

DistList (Exchange 2003 version)

DistList 2007 (Exchange 2007 version)

Documentation

Source code