How do I create a magazine type menu – sub-menu setup using wp_nav_menu and child of twentyten? [closed]

There are probably several solutions to this, but this is what I would do:

First set a static front page. This can be done in Settings->Reading.
This will cause the menu item (page) selected to have the CSS class current-menu-item and also to display any sub-menu items you have.

Then you just CSS them to be shown in a second row.