When you are looking at your "Manage Products" page. There are several ways to view your products. By default, the view will be set to only have the Parent of a Configurable Product visible (and not its sub items), as well as Simple items. If you want to be able to view a single certain items alternate ID items (the size, color, shape, etc..) then you would set the option "Make Simple Items Visible" to "Yes" in the Settings Category when editing a product, as shown below.
However, if you were looking to have Simple Items of Configurable Products visible for all of your products, this is done from the Manage Products page. While on this page, if you click on "More Options" and "Visibility: Show All", this will allow for all Simple Items of Configurable Products and all other products as well. This is depicted below.