...
my $pid = fork() or die "Can not fork!";
if ($pid == 0)
{
   # in child
   http->get("machine1:port1/process.cgi?arg1=val1&...");
   exit(0);
}

# in parent, kick off another process
$pid = fork() or die "Can not fork!";
if ($pid == 0)
{
   # in child
   http->get("machine2:port2/process.cgi?arg2=val2&...");
   exit(0);
}

...
and so on...