Is it possible to have the categories display on your blog,even if there isn't a post in that category? I'm starting a new blog with no posts, but I want visitors to see the topics I'm covering.
Yes you can. But first, I need to know if you are using a theme with widgets or not. It's much easier if you are not using widgets.
I don't use widgets and was afraid you might have to edit the widget code to get it to work. After a little searching, I found a widget that allows you to use all of the wp_list_categories parameters and tweak the display to suit your tastes. I just tried it on version 2.3.1 and it worked like a champ. You can download the plugin here. You get help with all the wp_list_categories parameters here. Just let me know if you have any other questions or need any help getting it setup.