dropdowns are just done with CSS, no need for special PHP stuff. Use wp_list_pages with your necessary excludes like you normally would, then style the output so it’s a dropdown menu.
in your header.php, right before the < / head> tag, insert this:
<!--[if lt IE 7]>
<style type="text/css" media="screen, tv, projection">
body { behavior: url("<?php bloginfo('template_directory'); ?>/code/csshover.htc"); }
</style>
<![endif]-->
Then open your style.css file, and add this:
/*------- Rolling Menu Styles ------------
Based on Menu from Jullij Theme https://www.jillij.com
*/
#menu {display: block;border: 0px;padding: 0px 0px 0px 0px;margin: 0px 0px 0px 20px;z-index: 5;position: relative;}
#menu ul {width:660px;min-height: 20px;line-height: 20px;list-style-type: none;padding: 0px 0px 0px 0px;margin: 0px 0px 0px 0px;z-index: 500; font-weight: bold;}
#menu li {display: inline;float: left;min-height: 20px;position: relative;text-align: left;padding: 0px 10px 0px;margin: 0px 0px 0px 0px;width: 100px;}
#menu li ul {width: 200px;height: auto;top: 100%;left: 0px; font-weight: normal;}
#menu li ul li {text-align: left;width: 200px; height: auto;min-height: auto;display: block;}
#menu a {text-decoration: none;}
#menu li li ul {top: 0;left: 0;}
#menu li li:hover ul {left: 220px;}
/* initialy hide all sub sidemenus */
#menu ul ul,
#menu ul li:hover ul ul,
#menu ul ul li:hover ul ul,
#menu ul ul ul li:hover ul ul,
#menu ul ul ul ul li:hover ul ul {position: absolute;display:none;color: #FFFFFF;}
/* display them on hover */
#menu li:hover ul,
#menu ul li:hover ul,
#menu ul ul li:hover ul,
#menu ul ul ul li:hover ul,
#menu ul ul ul ul li:hover ul,
#menu ul ul ul ul ul li:hover ul {display: block; color: #FFFFFF;}
/* define the consecutive colors */
#menu {color: #333333;}
#menu ul{background: #FFFFFF;-moz-opacity:0.95; /* for mozilla */opacity: 0.95; /* for safari */khtml-opacity: 0.95 /* for konquerer and older safari */}
#menu ul ul {background: #FFFFFF;}
#menu ul li {background: #FFFFFF;}
#menu h2 {color: #ffffff;}
#menu a {color: #333333;}
#menu a:hover {color: #ffffff;}
#menu ul li:hover {background: #3399cc;color: #FFFFFF;}
#menu ul li ul {}
#menu ul li ul li {background: #FFFFFF;}
#menu ul li ul li:hover {background: #3399cc;color: #FFFFFF;}
#menu ul li ul ul li{background: #FFFFFF;}
#menu ul li ul ul li:hover {background: #3399cc;color: #FFFFFF;}
Of course you need to adapt the colors, sizes and positions. But that’s basically it.
You’ll want to download the internet-explorer-7-anti-screwup-special-file you added to your header, so head on over to https://www.jillij.com/wordpress-theme/ (this is where I got the initial code from) and download the theme, then copy the necessary file called csshover.htc to your theme directory.
I used it on https://www.smarttimes.at as well, in case you want to do some css-comparing.