dropdown menu that supports ipad

I'm coding a design I've been given for a multisite project. The menu needs to be a dropdown menu and needs to work with the iPad - on some pages there isn't an option for a sidebar menu. Would like it to work on desktops on hover and work with 3.0+ menu system. Is there a plugin that can do this (or a tutorial)? Pages will be added and subtracted from both the main menu and submenus.