Do you mean getting the computer name from the IP? I think you may be looking for [man]gethostbyaddr()[/man]. Ex:
<?php
$hostname = gethostbyaddr($_SERVER['REMOTE_ADDR']);
echo $hostname;
// Ex: 192.168.1.2 INTO www.horearadu.com
?>
This does a DNS query so your getting a 'Internet host name'. If you want the NETBIOS name, like just horearadu, then I'm not sure how to do that.
