Here are two examples of the popular, well presented Tigra Menu from Denis at Soft Complex. This easy to configue script is in the form of several .js files which contain clear instructions making it easy to set up on your site. There is a ton of support supplied with this menu which can be found at http://menu.softcomplex.com along with other examples of the menu, and visit their forum for extra help. This script file downloaded from A1 JavaScript Resources contains the free version of Tigra Menu and contains the original files which are available from http://menu.softcomplex.com
Thanks to Denis Gritcyuk for this excellent script.