Microsoft IIS Web Server and ASP.NET Forum

I assume that Outlook Web Access intergrates with Active Directory? If so, do you know if there is a way that I can grab the session variables after a successful login on OWA to be read by an ASP or even a PHP script?

I ask, because one of our clients is looking for us to build them a login into their employee portal after they successfully log into OWA and they do not want the employees to have to log in twice. If anybody knows the answer, that would be cool.