The "problem" with NAV is that it will set the location of the submenu items (position, left and top in CSS) with JS, so the location is not easy to change.
With a regular unordered list menu that's easier.

I did not use the templated menu to be honest (I have use own custom menu component)
The CSS I would use is this:

For the menu container:
position:relative;

The sub menu item
position:absolute;
left:0;

(and with a negative value for "top" you could even get it above the main menu items I think)

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I figured it out. If anyone is interested in left aligning the submenu to the left-most edge of the menu container here is how you do it: (1) Create a DIV tag that is a menu wrapper. (2) Use these CSS settings for the menu wrapper position: relative; width:900px; margin: 0 auto; text-align:left; (3) Set your menu CSS this way: .mainMenu .m { left:0 !important;} Here is a link I found helpful: http://www.yourhtmlsource.com/stylesheets/csslayout.html