DrupalThemesOnly

First and foremost, there is really handy module that can help you set up templates for your blocks. This module gives you the ability to switch themes and styles by just navigating to your block admin page and clicking the select box for the template you want to use. You can get this module at http://drupal.org/project/blocktheme

That being said you are still probably wanting to know how to theme your blocks individually right. So here you go.

Coming Soon!