Adding a custom block
No point in me retyping this so follow this link
Look here for full instructions.
Note:
You do not need to create a seperate module for this. It can live happily in the skin module if you use the second method which is preferred. If you use the second method do not include the @List directive as it is already defined in /View/MyWidget.php between the namespace and the class declaration.
If you do it may appear twice.
For those that are really interested the View Lists are stored in the database in a table named xlite_view_lists.