I started working on an admin theme for Drupal over two months ago in my spare time and just got around to packaging it up offering it up for download. I've used it on a a few client's sites and they seem to like it so hopefully someone else can get some use out of it.
As you may or may not know Drupal has the ability to switch from your site's theme to an admin theme when the user is logged in as an admin and in the "/admin" URL. Typically I used the Garland theme for this purpose as it looks different than any theme I've made so it's easy to tell if you the user are in the "admin" area as opposed to viewing a site. Not to mention the Garland theme looks and and works great too.
The only annoyance I've had with switching over to an admin theme is that when you go to edit a page it takes you to the "edit" page but still uses your site's theme. This can get confusing as you are in the admin menu but yet your theme isn't using the admin theme you selected. To fix this I created a module for my theme which uses my Drupal admin theme for the "add", "edit" and "delete" pages.
Screenshot of my Drupal admin theme:
So if you download my Drupal admin theme be sure to install the module for it as well. Also be sure to activate it through the "modules" page. It probably won't work for everyone but it seems to do the job for me and my clients so far. Feel free to rip it apart and make it your own.
Ready to give it a try? Go ahead and download my Drupal admin theme.
You can also grab the module here.
If you like the theme or have any ideas on how to improve it please let me know as it's still a work in progress. I'm pretty sure I'll update it to Drupal 6 when that becomes officially released. It can also be used as a regular theme for your site - not just an admin theme.