I just completed putting together a drag and drop block management module for drupal. You can see a demo of it here.

If you do not want to implement this as a module you could take a look at client side management of blocks - which I had written about here with minor modifications to your theme files.

This lets you do the following:
- as an administrator for any theme you can now drag and drop the blocks between the regions to change your layout.
- from any individual node edit page you can hide/show the block on the page by clicking on the checkbox.
- as an administrator you can click on the block to be taken to its administration page.

The module uses the jquery interface plugin for its UI.