Here's an example using Text::CSV and XML::Twig to get you started:

use strict;
use warnings;
use Text::CSV;
use XML::Twig;

my $CSV = Text::CSV->new();
my $XML = XML::Twig->new(
    twig_handlers => {
        product => sub {
            my @data;
            push @data, $_->att('description');
            my $c_i = $_->first_child('catalog_item');
            push @data, $c_i->att('gender');
            ### Gather the other fields here, then...
            $CSV->print(*STDOUT, \@data);
            print "\n";
        },
    },
    pretty_print => 'indented',
);
$XML->parsestring(*DATA);

__DATA__
<?xml version="1.0"?>
<?xml-stylesheet href="catalog.xsl" type="text/xsl"?>
<!--<!DOCTYPE catalog SYSTEM "catalog.dtd">-->
<catalog>
  <product description="Cardigan Sweater" product_image="cardigan.jpg"
+>
     <catalog_item gender="Men's">
        <item_number>QWZ5671</item_number>
        <price>39.95</price>
        <size description="Medium">
           <color_swatch image="red_cardigan.jpg">Red</color_swatch>
           <color_swatch image="burgundy_cardigan.jpg">Burgundy</color
+_swatch>
        </size>
        <size description="Large">
           <color_swatch image="red_cardigan.jpg">Red</color_swatch>
           <color_swatch image="burgundy_cardigan.jpg">Burgundy</color
+_swatch>
        </size>
     </catalog_item>
     <catalog_item gender="Women's">
        <item_number>RRX9856</item_number>
        <price>42.50</price>
        <size description="Small">
           <color_swatch image="red_cardigan.jpg">Red</color_swatch>
           <color_swatch image="navy_cardigan.jpg">Navy</color_swatch>
           <color_swatch image="burgundy_cardigan.jpg">Burgundy</color
+_swatch>
        </size>
        <size description="Medium">
           <color_swatch image="red_cardigan.jpg">Red</color_swatch>
           <color_swatch image="navy_cardigan.jpg">Navy</color_swatch>
           <color_swatch image="burgundy_cardigan.jpg">Burgundy</color
+_swatch>
           <color_swatch image="black_cardigan.jpg">Black</color_swatc
+h>
        </size>
        <size description="Large">
           <color_swatch image="navy_cardigan.jpg">Navy</color_swatch>
           <color_swatch image="black_cardigan.jpg">Black</color_swatc
+h>
        </size>
        <size description="Extra Large">
           <color_swatch image="burgundy_cardigan.jpg">Burgundy</color
+_swatch>
           <color_swatch image="black_cardigan.jpg">Black</color_swatc
+h>
        </size>
     </catalog_item>
  </product>
</catalog>
[download]