#!/usr/bin/perl

use strict;
use warnings;
use XML::Simple;

my $data = {
  communities => [
    {
            name => 'perl-community.de',
            url  => 'http://www.perl-community.de',
    },
    {
            name => 'otrs-community',
            url  => 'http://www.otrs.org',
    },
  ],
};

my $xs = XML::Simple->new;
my $xml = $xs->XMLout( $data );
print $xml;

perl xml_simple.pl
<opt>
  <communities name="perl-community.de" url="http://www.perl-community.de" />
  <communities name="otrs-community" url="http://www.otrs.org" />
</opt>