You could use eg. XML::Rules, somewhat like this:

use XML::Rules;

my $parser = XML::Rules->new(
  rules => [
    Item => sub { $_[1]->{Name} => $_[1]->{_content}},
      # take only the name and content from the <Item> 
      # and make it available using the Name as the key
    Id => 'content',
    DocSum => sub {
      print "Id: $_[1]->{Id}\nName: $_[1]->{Name}\nFoo: $_[1]->{Foo1},
+ $_[1]->{Foo2}\n\n";
      return; # we are done with the <DocSum>, no need to keep the dat
+a
    },
  ]
);

$parser->parse($the_file);
[download]

Basically the Item and Id rules specify what and how do you want from those tags and the DocSum consolidates the data from the subgtags and processes it the way you need. The (posibly) important difference from XML::Simple is that you process the XML gene by gene, instead of parsing the whole file, creating a possibly huge datastructure and then processing that structure.

You may want to have a look at XML::Twig and CPAN::XML::LibXML as well.

Update 2007-6-14: fixed a typo in the code.