Something like this perhaps

use strict;

use threads;
use threads::shared;

print "Started\n";

my $status : shared = 0;

my $thr1 = threads->new(
    sub {
        sleep(1) and print "thread1: $status\n"
            while 1;
    }
);
my $thr2 = threads->new(
    sub {
        sleep(1) and print "thread2: status incremented\n" 
            while ++$status;
    }
);

$thr1->join;
$thr2->join;

__output__

Started
thread1: 1
thread2: status incremented
thread1: 2
thread2: status incremented
thread1: 3
thread2: status incremented
thread1: 4
...
[download]

This requires perl5.8.0 compiled with threading, or with a slight modification, perl5+ without threading and using the inspired forks module.
HTH

_________
broquaint

update: fixed forks link per RMGir's node