I have been looking into this for some time and spent most of the morning researching it. It is just unbelievable the lack of integration.
We have Office 365 and use Outlook 2007/2010 on our computers and of course have OWA. So, I have a group of people that would like to share a calendar so they can be at the same meetings or see what the others have scheduled that might benefit the group. Of course, an Outlook user can share their calendar. This will go on the Outlook program of others in the group, and also will go to the OWA. However, you can't see these shared calendars on your Windows Phone if they aren't yours.
Then I set up a Public Folder in Exchange and made a calendar. Cool, everyone has this on their Outlook program on their computer and they can all see and add things to the calendar. BUT, public calendars don't show up in OWA, and of course then, they don't show up in a Windows Phone.
So, how about the Rooms in WP, which is a cool feature. In fact, everyone in this group has a Windows phone, except for the admin assistants. Of course, we want the admin assistants to be able to put group meetings on their Outlook program so it syncs to the Windows Phone Rooms calendar everyone else has. Don't see any way to link the Rooms calendar unless you use something like Outlook Connector and set up a Microsoft account.
If anyone has any solutions for this simple problem, post it here.