The easiest way to get started is with XML::Simple. It reads in XML and transforms it into a perl data structure:

  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]

prints out

  $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]