Nested Menu

[mvlcek]

Nested Menus:
http://get-simple.info/extend/plugin/nested-menus/256/
Child Menu:
http://get-simple.info/extend/plugin/child-menu/40/

I think the plug-in 'nested menus' is what you're looking for, but I have not used it, but between it and CSS I think you should be able to arrive at what you want.
'Child menu', I have used in a sidebar setup with CSS, but not as a drop-down although it could be made to work using JQuary.

I Know Of The Plugins But None Can Make DropDown Menus

If you have a nested menu, it's just a matter of CSS to make a drop down menu, e.g. see http://mvlcek.bplaced.net/multi-level-na...down-left/ for basic CSS rules.