Here is a very nice top navigation bar for your website.

It uses CSS3 & jQuery to give a nice looking aero gradient & transparency effect.

The CSS

The CSS uses some of the new CSS3 features such as box shadow and gradients.

Here’s all the CSS needed to display the nav bar :

.menu_wrap {
    left: 0px;
    top: 0px;
    right: 0px;
    z-index: 999;
    width: 100%;
    height: 50px;
    background: -moz-linear-gradient(top, #b8e1fc 0%, #a9d2f3 10%, #90bae4 25%, #90bcea 37%, #90bff0 50%, #6ba8e5 51%, #a2daf5 83%, #bdf3fd 100%); /* firefox */
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#b8e1fc), color-stop(10%,#a9d2f3), color-stop(25%,#90bae4), color-stop(37%,#90bcea), color-stop(50%,#90bff0), color-stop(51%,#6ba8e5), color-stop(83%,#a2daf5), color-stop(100%,#bdf3fd)); /* webkit */
    -webkit-box-shadow: 0px 2px 5px #000000;
    -moz-box-shadow: 0px 2px 5px #000000;
    box-shadow: 0px 2px 5px #000000;
    position: fixed;
    margin-top:-30px;
}
.menu_links ul {
    margin: 0px;
    padding: 0px;
    list-style-type: none;
}
.menu_links ul li {
    display: inline;
}
.menu_links ul li a {
    float:left;
    line-height: 50px;
    padding-right: 20px;
    padding-left: 20px;
    color: #FFF;
    font-size: 22px;
    text-decoration: none;
    text-shadow: -1px -1px 1px #333;
    display: block;
    border-right-width: 1px;
    border-right-style: solid;
    border-right-color: #FFF;
}
.menu_links ul li a:hover {
        color: #000;
        text-shadow: -1px -1px 1px #EEE;
    background: #ffffff; /* old browsers */
background: -moz-linear-gradient(top, #ffffff 0%, #f1f1f1 50%, #e1e1e1 51%, #f6f6f6 100%); /* firefox */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#ffffff), color-stop(50%,#f1f1f1), color-stop(51%,#e1e1e1), color-stop(100%,#f6f6f6)); /* webkit */
}
.menu_buttons {
    float:right;
    line-height: 50px;
    height: 50px;
    margin-right: 30px;
}
.menu_buttons ul {
    margin: 0px;
    padding: 0px;
    list-style-type: none;
}
.menu_buttons ul li {
    display: inline;
    height: 50px;
}
.menu_buttons ul li a {
    float:left;
    padding-right: 10px;
    display: block;
    border:none;
    line-height: 50px;
    padding-left: 10px;
    height: 50px;
    padding-top: 10px;
     }
.first {
    border-left-width: 1px;
    border-left-style: solid;
    border-left-color: #FFF;
}
.menu_links {
    height: 50px;
    float: left;
    margin-left: 100px;
}

The HTML

The HTML is very straight forward and can be changed to display different menus etc.

<div class="menu_wrap">
    <div class="menu_links">
      <ul>
        <li><a class="first" href="#">Home</a></li>
        <li><a href="#">About</a></li>
        <li><a href="#">Contact</a></li>
        <li><a href="#">Links</a></li>
      </ul>
    </div>
    <div class="menu_buttons">
          <ul>
        <li><a class="first" href="#"><img src="facebook.png" alt="Facebook" width="32" height="32" border="0"></a></li>
        <li><a href="#"><img src="twitter.png" alt="Twitter" width="32" height="32" border="0"></a></li>
        <li><a href="#"><img src="delicious.png" alt="Delicious" width="32" height="32" border="0"></a></li>
        <li><a href="#"><img src="rss.png" alt="RSS" width="32" height="32" border="0"></a></li>
      </ul>
    </div>
</div>

The jQuery

The jQuery is perhaps the most important as it controls the transition effects.

The jQuery used is quite simply to understand and doesn’t use any advanced features.

The main functions in use are Hover, CSS & Animate.

<script type="text/javascript">
$(document).ready( function () {
    if($.browser.msie){
    $('.menu_wrap').css({'background-color' : '#b8e1fc','position' : 'absolute','width' : '100%'});
    }
    $('.menu_wrap').css({'opacity' : '0.3'});
    $('.menu_wrap').hover ( function () {
        $(this).animate({'margin-top' : '0px','opacity' : '1'});
        $('.menu_buttons img').animate({'opacity' : '.5'});
    }, function () {
        $(this).animate({'margin-top' : '-30px','opacity' : '0.3'});
    });
    $('.menu_buttons img').hover ( function () {
        $(this).animate({'opacity' : '1'});
    }, function () {
        $(this).animate({'opacity' : '0.5'});
    });
});
</script>

The article source:http://www.bitsntuts.com/css/pretty-css3-jquery-top-bar-navigation