Actually the hotscripts link mentioned in the 1st post here is for megaupload. As the megaupload site points out, PHP by it self is not capable of tracking the transfer of an upload. It tried the PHP/cgi version of megaupload and it operates as advertised.
See this recent thread on this -
http://www.programmingtalk.com/showthread.php?t=26703
I did not check out the link in the last post in that thread. It mentions a patch for PHP (most users would not be able to make use of such a solution in a hosted environment.)