I\'m writing a CMS application in PHP and one of the requirements is that it must be able to interface with the customer\'s Exchange server. I\'ve written up this functiona
https://github.com/Garethp/php-ews
It was last updated 3 months ago so it is maintained
This Zarafa PHP MAPI extension looks like it could work.
Is your customer using Exchange 2007? If so, I'd have a look at Exchange Web Services. If not, as hairy as it can be, I think WebDAV is your best bet.
Personally I don't like using the Outlook.Application COM object route, as its security prompts ("An application is attempting to access your contacts. Allow this?", etc.) can cause problems on a server. I also think it would be difficult to accomplish your impersonation-like tasks using Outlook, such as sending mail as a given user.
I have released an open-source MIT licensed library that allows you to do some basic operations in PHP using Exchange Web Services.
Exchange Web Services for PHP
I have only tested it on Linux but I don't see any reason why it wouldn't work on a Windows installation of PHP as well.
I would look into IMAP
IMAP, POP3 and NNTP
I would recommend using "PHP Exchange Web Services" or short php-ews.
Fair amount of documentation under the wiki, helped me a lot.