Wes Haggard, one of the Outlook developers, has a good blog post over on his blog about how to properly access Outlook PIM data in a server style application.  Since the Outlook OM isn't supported in this configuration, Wes outlines how to use WebDAV, Exchange web services, and ADSI to query some of this data.

I know this is a common question that a lot of developers have when building solutions, so it's great Wes took the time to develop some quick samples on how it can all work.