Temporary example - Koha OPAC theme using templates + css <http://www.library.nsw.org.au/>
Main Link to Koha Templating http://koha.org/contribute/templating/
HTML::Template http://www.perldoc.com/cpan/HTML/Template.html
Web Design Group http://www.htmlhelp.com/
Recommended by Katipo http://www.richinstyle.com/
Docbook Publishing Brockmeier and Pritchard, Primatech's linux series
Extreme programming (see list)
O'Reilly published Perl Series