162517 Nav Bar Dropdown Addon

Hi, I have a nav bar already created that you can see here: [login to view URL] I'd like to add drop down menu functionality to these tabs like this picture I made in photoshop: [login to view URL] The nav bar must be cross browser functional in FF, IE and Safari. Also this nav bar is something I'll be distributing so there can't be any code used that is copyrighted. Also if this can be done in Ajax that would be cool too. Thanks! Dino