See http://thelackthereof.org/projects/perl/oddmuse_pingback/ for source (and darcs repo).

I would appreciate it if people could link to this page in a pingback-enabled post of some kind so that I can make sure it works. The only way I've tested it is with http://software.hixie.ch/utilities/cgi/pingback-proxy/client.html this client, which has worked swimingly.

This is the first step. Second would be to make oddmuse work as a pingback client too. The trick there is to make sure we aren't over-pinging links and I'm not sure how that should be done.