The first question youhave to ask yourself is how dynamic your content really is? I tend to store data in XML but then I generate static XHTML from it, so the server is not burdened by the XML processing each time a page is served. Of course you can also put a cache in front of it and then it is dynamic for you but mostly static for the users.

If you want a truly dynamic site you might want to look into AxKit, and read the XML application servers thread. AxKit will let you define stylesheets applied to your XML data and it will take care of the caching. Be ready to learn XSLT or XPathScript though.

As for resources on Perl and XML, Data Munging with Perl by Davorg has a section on XML that describes XML::Parser and XML::DOM, the Module Reviews section here has got a bunch of reviews of XML modules, xml.com has got a number of articles on Perl and XML, look for Kip Hapmton's column, and I have a list of articles, mostly about Perl and XML, all linked from here. Generic info on XML can be found on The XML Cover Page which has a (short) section on XML and Perl.