I needed a simple way to display subcategories under categories (always expanded) for VirtueMart. I spent hours searching the forum with no answers, but this extension did the trick perfectly!!!

It's not free, but well worth the modest cost (10Euro, approx $15US) and is painfully simple and easy to use.

A couple of hints - Remove the CSS completely from the template file, located in modules/vmcategorymodule/vmcategorymodule_tpl.html If you don't, you will have the styling appear for each and every item. You can easily style the div's and links in your regular template CSS.

Thanks for this awesome module!