#!/usr/bin/perl -w
use strict;

use LWP::UserAgent;
my $ua = LWP::UserAgent->new(agent => "", timeout => 30);

my $url = 'http://example.com/index.php?do=action';

[... some parameter checking]

for my $i (@ARGV[2..$#ARGV])
    {
    my $response = $ua->post($url, [ value0 => $ARGV[0],
        value1 => $ARGV[1], value2 => $i, Submit => 'Submit' ] );
    if (not ($response->is_success))
        { die "Can't retrieve page: " . $response->status_line . "\n"; }

    my $page = $response->content;

    [... process content]

    }