subcategories visual kind. Help Please!

Hi!
There was a problem with visual kinding of Parental categories and subcategories, standardly they “are moulded” in one heap, and it would be desirable to have such appearance:

Category 1
- A subcategory 1.1
- A subcategory 1.2
...
  Category 2
- A subcategory 2.1
...

For a long time I try to understand it, but to sense is not present while. I know only, that for visual kinding of categories the tag wp_list_categories (for new versions from 2.1 and wp_list_cats for old) in sidebar.php answers. Also for kinding of this tag answers registered in sidebar.php a class (css), but here I do not understand as this all to register, i.e. it is even not clear as in a file of style it to register? May be files category-template.php or category.php need to moderate…

P.S. It would be good to combine still it with a plug-in MyCategoryOrder which allows to interchange the position parental categories visually. This would be super! 🙂
THANKFUL IN ADVANCE!