use Data::Dumper;
  use XML::Simple;

  my $ref = XMLin(\*DATA);
  print Dumper($ref);

  __DATA__
  <result>
    <cd serial="001">
        <artists>
           <artist>Smashing Pumpkins</artist>
        </artists>
        <title>I Am One</title>
    </cd>
    <cd serial="002">
        <artists>
           <artist>Foo Fighters</artist>
           <artist>Smashing Pumpkins</artist>
        </artists>
        <title>The Shield Soundtrack</title>
    </cd>
  </result>
[download]

  $VAR1 = {
    'cd' => [
      {
        'artists' => {
          'artist' => 'Smashing Pumpkins'
        },
        'serial' => '001',
        'title' => 'I Am One'
      },
      {
        'artists' => {
          'artist' => [
            'Foo Fighters',
            'Smashing Pumpkins'
          ]
        },
        'serial' => '002',
        'title' => 'The Shield Soundtrack'
      }
    ]
  };
[download]

I'd suggest reading the XML specs, and learn to read DTDs.

Yes, you can use XML without understanding its intricacies, but there's no real substitute for actually knowing what you're working with.

Everyone has their own favorite XML modules in CPAN ... search on 'XML' in the Super Search, and you'll find lots of recommendations. Without knowing the intricacies of what you're trying to parse and/or create, I'd be doing a disserve to suggest any particular one.

Not specific to Perl, but tips for getting the lay of the XML land:

Altova offers a free "Home Edition" of XMLSpy, which can be a very handy visual aid for those learning about XML, what it looks like, how to edit it, how to get started with "offshoots" like XML Schema, XSL/XSLT, etc.

refcards.com has a few reference cards on XML and related technologies. (I learned about that site from Perlreref as formatted quick reference.)

Zvon has many similar materials, freely downloadable, comprehensive, in various formats and numerous languages.

As far as learning about new modules and/or code snippets, I have found the bundled documentation helpful ;-). But don't forget about utilities such as POD2HTML... Other helpful creatures in this beastiary include podgen, DoxyFilt* (Doxygen for Perl), and Perl::Tidy.

Some books I have found useful are: XSL Essentials, XSLT, XSLT Cookbook, and of course, The Perl Cookbook, 2nd Ed.

HTH,

Update: See also Perl-XML Frequently Asked Questions and Frequently Asked Questions about XML::Simple

* Update: 2005-12-28 Kudos to both john_oshea and tfrayner for alerting me to the fact that my link above has been rendered usless by the foul creatures known as spammers... I have found what appears to be a good link to obtain DoxyFilt; the most recent version seems to be from August 24, 2005: Doxygen-0.84.tar.gz. Thanks again, guys!

* Update: 2006-03-11 Like Zvon, deepX has a good collection of "Quick References" on XML-related technologies such as XPath, XSD, XSL and XSLT (and even CSS and MySQL!).

I appreciate I'm going against a lot of previous recommendations here, but I really don't think module::XML::Simple is that simple. Whilst the interface is nice and simple the actual Perl data structure that comes back can seem amazingly crufty, with things changing from scalars to array refs when there's more than one subnode, and othersuch trickery. I ended up giving up on this for that reason, I appreciate though that others do have different opinions on this (Re: Vi vs. Emacs) so just take this as an alternate view.

My personal recommendation for handling XML, regardless of your initial level of proficiency, is XML::LibXML. This is a very large and complex module, and can be a nightmare to get working due to it having a C library dependancy (libxml, oddly enough). Where it does shine is by providing a simple interface to XPath in the XML::LibXML::node::findnodes() command. XPath is the only technology I've seen which makes pulling out stuff far down an XML structure easier than pulling teeth. Another, possibly lesser, advantage is that if you should ever now need to do some heavier-duty stuff in XML you have experience in one of the most adaptable XML modules- less retraining time.

You may also want to have a look at the "Perl and XML" book by the shiny O'Reilly people if you're thinking you'll end up doing a lot of XML, it's a thin book but it does allow you have an overview of a lot of different approaches.