Resolution
Although you cannot change the date format used for the column headers in the My Tasks page, you can change how the system displays the date in any date field, such as the Start and Finish fields. To do this, the Project Server administrator should complete the following steps:
1. Log into PWA with administrator permissions.
2. Click the My Tasks link in the Quick Launch menu.
3. Click the Site Actions menu button (upper right corner of the page) and select the Edit Page item on the menu.
4. In the My Tasks web part, click the Edit pick list (upper right corner of the Web part) and select Modify Shared Web Part on the pick list.
5. In the sidepane that opens on the right, scroll to the bottom and expand the Project Web Access section.
6. Click the Date Format pick list and select the desired date format, such as Weekday/Date.
7. In the sidepane, click the OK button.
8. Click the Exit Edit Mode button (upper right corner of the page).
NOTE: To view the day of the week for the date in any column header, simply float your mouse pointer over the date. Project Server 2007 will display the day of the week plus the long date in a Tooltip.