Re: Showing all categories / editing post.
There is another forum post which explains how to do this. You basically change a parameter in the index.php file.
Code:
<?php wp_list_categories('show_count=0&hide_empty=true&orderby=name&order=asc&title_li='); ?>
Change the hide_empty=false and it should work.
The user has their own dashboard where they go and edit their ads. It's the dashboard link at the top.