MHonArc is a powerful email-to-HTML tool, used typically as a web interface to email list archives.
It has some interesting Perl code that's relevant to InternationalisationUTF8, having gone through the I18N process somewhat earlier than TWiki, with particularly good support for diverse character sets/encodings.
See http://www.mhonarc.org/ for details.
-- RichardDonkin - 18 Sep 2003