The company that I work for has migrated their local exchange to a hosted Office 365 solution. We are in the process of building out several externally(to our local network) hosted websites and would like to use PHP authentication to build upon our existing, hosted user base.
Can anyone explain or point to some documentation of a way to use PHP to connect to a remotely hosted AD (in this case Office 365) and authenticate users to it and also how to get access to the calendar events of the logged in user
Thank you for your time and effort.
You can use PHP's LDAP functions just as you would for a self-hosted Active Directory Server.
Microsoft has some information on this themselves: Web Single Sign-On with PHP and Windows Azure Active Directory