Drop down menus are not usually the best solution anyway so if you can avoid using them all the better.
Some devices (iphone, ipad) will allow dropdowns to work (such as this one) if they have been constructed with links in place and tapping the item will show the dropdown and then a link can be selected from the dropdown with anther tap. The problem arises in that if you decide not to navigate away the menu stays open and will only close if you click another link somewhere on the page. Therefore an option would be to script the hover function as a click function for touch devices.
Stu Nichols has some examples for the iDevices here.