Woodweld-
If you click on the Due On column header it will temporarly change the sorting of the column. To change the defaults you would have to make a copy of the screen (CRM_ActivitiesList) and edit the grid. Once you edit the grid you can set the default filter view and change the default sort order.
-Michael
Michael Melo
Product Manager
Method Integration Inc.
Website: http://www.method.me
LinkedIn: http://www.linkedin.com/in/MichaelMelo