This is a common question, take your pick of the answers:

• XML parser
• which XML module?
• perl/XML development
• XML::Twig, or something else?
• Which XML module to use?
• XML parser
• XML and Perl
• XM-Hell
• XML Module decision tree?
• Mirod's Ways to Rome & Ways To Rome 2
• Kip's Column on XML.com
• Using XML Modules in Perl