In the Microsoft Outlook Web App 2010 you can check delivery reports for your sent mail and even mail that was sent to you. Please follow the instructions below.
Login to Outlook Web App.
Choose Options in the upper right hand corner. Then choose “see all options”.
Choose “Organize E-Mail” from the menu on the left. Then select “Delivery Reports”.
You can now choose either “Search for messages I’ve sent to: or “Search for messages that were set to me from:” You must select the user by clicking “Select users” and then choosing the user from the Global Address List (GAL) or your contacts list.
After you have selected your user, you can enter key words to search the subject line of messages. (This is recommended if you have many messages sent to or received from the selected sender or recipient.)
Choose “Search” and view your results.
Now that your search has finished, you can choose to view the details of a certain message by clicking on the message and then selecting “Details”.
You can now see some details of the email transmission.