Exchange 2010 (download) provides an easy way to verify whether that very important message was delivered to every recipient with a new feature called ‘delivery reports’. Delivery Reports contains delivery information about messages you sent, and about messages you received, and can be accessed by users from Outlook Web Access or by clicking on the "Options" button and then going to "Organize E-mail". Administrators can access Delivery Reports from the Exchange Control Panel on the "Reporting" tab, and if the Administrator has access to the Exchange Management Console, the "Toolbox" section contains a link to "Message Tracking" where they can search for Delivery Reports. The Message Tracking tool included in previous versions of Exchange has been renamed "Tracking Log Explorer".
Full Article: Exchange Team