How to handle drop-down navigation

I’m in the process of implementing Responsive Design on my wife’s business’s website, and I’m trying to decide how to handle the horizontal nav menu with drop-down items.

Is there a “best practices” way of handling this? One thought I had (and which I used to swap footers) was to have two separate HTML versions, and use #display: none; in the regular stylesheet to hide the mobile footer, and vice versa.

How do you guys handle drop-down menus for mobile devices?

A bit late with my answer but these are the usual approaches.

I like the menu icon approach also favoured by bootstrap.

Just remember though, Apple require all browsers to be webkit-based.

Opera Mini of course works in a different way.