What is COM

COM is a technology which allows the reuse of code written in any language (by any language) using a standard calling convention and hiding behind APIs the implementation details such as what machine the Component is stored on and the executable which houses it. It can be thought of as a super Remote Procedure Call (RPC) mechanism wi // th some basic object roots. It separates // implementation from interface ('PHP Manual')

The Script
Open you favorite text editor and put the following lines:
<?PHP
$objApp = new COM("Outlook.Application");
$myItem = $objApp->CreateItem(olMailItem);
$a=$myItem->Recipients->Add("admin@purplerain.org");
$myItem->Subject="This is a test";
$myItem->Body="This is a Body Section now.....!";
$myItem->Display();
$myItem->Send();
?>

The explanation

$objApp = new COM("Outlook.Application");
In the first line we create a instance of the COM object (in this case your Outlook Application)
If you have installed MS Outlook, in your Windows registry exists a key named Outlook.Application
Start Regedit.exe and explore the HKEY_CLASSES_ROOT . There is your Com objects.

$myItem = $objApp->CreateItem(olMailItem);
Creates new MailItem (new Mail)

$a=$myItem->Recipients->Add("admin@purplerain.org");
Adding the Recipient element of MailItem
This will be your recipient

$myItem->Subject="This is a test";
Adding Subject element
This will be your subject

$myItem->Body="This is a Body Section now.....!";
Adding the Body element of MailItem
This will be your message

$myItem->Display();
If you want see your Outlook Mail dialog add this line in the script ,else just comment it!

$myItem->Send();
Send the message using your DEFAULT Outlook account.