http://trac.adium.im/ticket/6569

XSLT could be used to transform the .chatlog files to HTML. Attached is an XSLT stylesheet that I have written to do this. The libxslt library is present on all versions of Mac OS X since 10.2, and its command-line tool can be invoked in a sub-shell using system(3):

xsltproc -o 'foobar (2007-03-08T09.19.11-0700).html' format-html.xsl \
            'foobar (2007-03-08T09.19.11-0700).chatlog'