use Parallel::ForkManager;
  use LWP::Simple;

  my $pm = Parallel::ForkManager->new(10);

  LINKS:
  for my $link ('http://us.a1.yimg.com/us.yimg.com/i/ww/m5v9.gif',
  'http://hooboy.no-such-host.int/',
  'http://www.yahoo.com',
  'http://www.ora.com/ask_tim/graphics/asktim_header_main.gif',
  'http://www.guardian.co.uk/',
  'http://www.pixunlimited.co.uk/siteheaders/Guardian.gif') {
    $pm->start and next LINKS;    

      my ($content_type, $document_length, $modified_time, $expires, $server) = head($link);
      print "$link fetched: declared lenght $document_length, \n";   

    $pm->finish;
  };

# output

http://hooboy.no-such-host.int/ fetched: declared lenght ,
http://us.a1.yimg.com/us.yimg.com/i/ww/m5v9.gif fetched: declared lenght 5611,
http://www.guardian.co.uk/ fetched: declared lenght 628397,
http://www.ora.com/ask_tim/graphics/asktim_header_main.gif fetched: declared lenght ,
http://www.pixunlimited.co.uk/siteheaders/Guardian.gif fetched: declared lenght ,
http://www.yahoo.com fetched: declared lenght 12,