use LWP::UserAgent;
my $ua = LWP::UserAgent->new;

my $req = HTTP::Request->new(POST => 'http://www.foobar.com/cgi-bin/foobar');
$req->content_type('application/x-www-form-urlencoded');
$req->content('foobar=5');

my $res = $ua->request($req);
print $res->as_string;