my $t = XML::Twig->new( twig_handlers => { 'Phones'=> \&phones } );
$t->parse($xml);

sub phones {
  my ($t,$elt) = @_;
  print $elt->parent->att('name');;
  print ' Phone = ',$t->last_elt('Phone[@name="cell"]')
                      ->att('number'),"\n";
  print "\n";
}