Select the Announcements tool from the Tool Menu in the Administration Workspace.
There are also three options that allow you to auto-sort the Announcements:
When you click the columns heading link, an icon appears beside it showing if the list is sorted smallest to largest, or largest to smallest. In the above illustration, the announcements are sorted by subject in A - Z order. If the subject heading is clicked again, the icon will point down showing that sort order has changed to Z - A.