There is a short article about frontpage with regions in Theme developer's guide. It offers some advices how to achieve this by using defined block regions. In my opinion, this solution is not easy to stylize. Far better solution lies in Panels Module.
"This module allows you to create pages that are divided into areas of the page." You can define arbitrary areas and then assign a view, block, custom new content or existing content to every area. Every area may have more than one content. Additionally is possible to set css id to all areas. This allows you to simply theme the frontpage via css.
