A Python/Twisted library for working with messages in many different formats and protocols. Depends on Python 2.3 and Twisted 1.3.
I gave a talk on Yarn at PyCon 2005. I've been told that audio will be available at some point (keep an eye on the PyCon 2005 TalkRecording wiki page). Ted Leung has notes on my talk. You can also download the slides in OpenOffice, PDF, or Flash.
See Abe's weblog
abe at fettig dot net