Need help inserting images into custom menus in WordPress

This should be pretty simple. I build WordPress themes using Artisteer, however my knowledge of CSS is limited. I need to be able to create a custom menu in WordPress, then use CSS to insert button images to replace the text. I found some tutorials but I'm missing something. I don't understand CSS enough to do it. I'm hoping to find someone who can show me how to insert the proper code to create the custom navigation buttons. Here are a few resources on what I'm trying to do: [login to view URL] [login to view URL] [login to view URL] Thanks!