Under Administration in the Admin section is Edit Categories. This is where you setup your public categories (weddings, newborns, events).
In the Edit Usergroups you can determine which usergroups have "Assign Albums to Cats?" permissions. Setting this to YES means that anyone in that group can select a category from the dropdown list inside their ALBUM ADMIN area (edit album) to assign it to a category.
http://www.viperalley.com/gallery/sh...ry.php/cat/503
If you scroll down, you will see several albums which have been assigned to this category.