use LWP::Simple;
use URI::URL;

my $url = url('http://www.perlmonks.org/index.pl?node_id=32057&lastnode_id=3628');

# Yes, the following is insecure and can be sniffed!

$url->query_form(username => 'joe',
                 password => 'schmoe');
$content = get($url);