i've been working on this for quite some time now in php and i have understood that threading within php itself is not possible, instead i use the multitasking capabilities of the OS (xp in my case) and start 3 different php scripts at the same time..
and i dont mean opening 3 pages in a web browser... go to the shell and type
"PHP -q scriptname.php"..
a batchfile like this may also be handy:
@ off
:a
php -q scriptname.php
goto a
oz