Blocks

I finally found the two articles on A List Apart on horizontal menus I remembered:

"Drop-Down Menus, Horizontal Style"
http://www.alistapart.com/articles/horizdropdowns/

"Suckerfish Dropdowns"
http://www.alistapart.com/articles/dropdowns/

Note that all tutorials mentioned above use an unordered list as a starting point which unfortunately isn't given with Moodle 1.9's Admin menu.

Another tip:
Use Development:Firebug and Stylish for testing CSS modifications.
See CSS FAQ and Themes FAQ for further information.

Cheers,
Frank