use HTTP::Request::Common qw(POST);
use LWP::UserAgent;
use LWP::Debug qw(+);
my $ua = LWP::UserAgent->new();
$ua->cookie_jar({});
$ua->agent('Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)');
my $req = POST 'https://login1.swipnet.se/login.php', 
[username => 'xxxxx', password => 'yyyyy'];
print $ua->request($req)->as_string;