The List selection form is the second form on the BackPing Database page. The drop down box contains the names of all the lists in the database. Blogs in the currently-selected list are marked with a smiley face in the list on the right side of the page.
To change the currently-selected list, choose a different list in the drop-down box and click the CHANGE LIST button.
You can create a new list by clicking on the Create new list link in the form. This takes you to a new page where you can enter the name for your new list and select via checkboxes the blogs to include in the new list. The list creation form is very crude, and there is currently no way to delete a list. Bruce is working on it.