According to the feature matrix comparing Outlook Web Access to Outlook on Microsoft's site, Outlook Web Access is a built-in component of Exchange Server 2007. It offers most email, some calender, some productivity, and some of the other functionality of Outlook 2007 paired with Exchange. Perhaps that's the first place to look, as it already integrates with Exchange and all.

You'll need far more for this sort of thing than just a template system or web framework. You'll also need at least:

• DBI and a suitable DBD for your SQL database
• Net::LDAP for access to ActiveDirectory (which would also be handy if you were making your own phone book/address book app)
• some connector to Exchange if you want the calendering to mate with that
• an RSS reading and perhaps aggregation module

You'll also need some other parts (some of which will be provided by some web frameworks) if you don't tie directly into Exchange's data for these parts:

• Date or Time modules for separate calender functionality
• some way to manage user accounts (creation, deletion, authentication, editing)
• some way to manage the sessions of the logged-in users
• an interface to get your address book data into and out of an SQL database or an LDAP directory

There are parts of this intranet of yours out there, but you'd have to piece them together. Getting them to work in an integrated way could be a hassle. Consider what Microsoft offers already made since you're tied to the Windows/IIS/Exchange platform.