In order to share the assembly with all the applications it needs to be installed in the GAC (Global Assembly Cache)
gacutil /i c:\tgol\phpclass\bin\phpclass.dll
This utility could be found in C:\Program Files\Microsoft Visual Studio .NET\FrameworkSDK\Bin (on my computer)
[Note] To view all the assembly installed in the GAC on your computer, open your windows explorer and look in assembly folder under windows folder C:\WINNT\assembly ( on my computer) [End Note]
Coding the PHP File
Create a text file with the following content and save the file as phpnet.php in c:\inetpub\wwwroot folder (or your webserver http root folder)
<?php
$MyObj = new COM ("phpclass.HealthRecord.patient");
$MyObj->lmp = "05/08/2002";
echo "LMP : $MyObj->lmp";
echo "<br />EDD : $MyObj->edd";
?>