use threads;
my $user="xxx";
my $password="yyy";

sub my_thread_sub
{
my ($url)=@_;
my $cookie=to_string ($url); # to string convert url to an acceptable filename
my $WGET;
if ( -e $cookie )
{
    open $WGET, "wget -q -O - -w 1 -T 1 -t 1 --load-cookies $cookie --user $user --password $password $url |";
}
else
{
    open $WGET, "wget -q -O - -w 1 -T 1 -t 1 --save-cookies $cookie --keep-session-cookies --user $user --password $password $url |"
}
local $/;
$output=<$WGET>;
...
return 0;
}
my @thrs;
my @urls=qw("http://example1/" "http://example2/");

dontgo:
my $i=0;
foreach my $url (@urls)
{
        $thrs[$i]=threads->new ("my_thread_sub",$url);
        $i++;
}
foreach my $thr (@thrs)
{
        $thr->join;
}
sleep 3
goto dontgo;
exit 0;