Your tasks can only be shared if both parties are using the Outlook client (2010). It is not possible using Outlook Web App (OWA).
To give someone access to your Tasks in Outlook 2010:
- Click the Tasks button (in the left Navigation Pane).
- Click on 'Tasks' under your 'To-Do' List (in the left Navigation pane)
- Only if you have tasks, the 'Share Tasks' button is available in the toolbar/ribbon, click this.
- Click the 'Share My Tasks…' link towards the bottom of the Tasks Navigation Pane.
- Like sending an email, enter the name of the person to whom you want to grant sharing permission (click on 'To...' button to bring up Global Address List).
- Select the required permissions and optionally add a message for the recipient, click 'Send'.
Opening another person's shared tasks
Shared Tasks can be opened and viewed side-by-side from the Tasks view in Outlook. To open another person’s Tasks:
- Click the Tasks button in the Navigation Pane and then the 'Open Shared Tasks' from the toolbar/ribbon.
- In Open a Shared Tasks dialog box type the name of the account you wish to access or click 'Name' to select the account from the address book. Click OK.
- The new Tasks list will be displayed and listed in the My Tasks section of the Navigation Pane.
- To access the Tasks just click on the relevant “Tasks in Mailbox - <<account name>>” listed in the Navigation Pane.