When working with Exchange, it is often necessary to fetch some informations from Active Directory. This helper library has this functionality:

• Find a user in a multi-domain forest based on his domain\username.
• Construct the URL for mailbox of a given user, based on his domain\username. This URL can then be used for WebDAV queries.
• Get a DirectorySearcher for the Global Address list and all the other defined address lists

Full source included, and, believe it or not, documentation :-)