Example

#dolphincontainer{position:relative;height:56px;color:#E0E0E0;background:#143D55;
width:100%;font-family:Helvetica,Arial,Verdana,sans-serif;}

#dolphinnav{position:relative;height:33px;font-size:12px;text-transform:uppercase;
font-weight:bold;background:#fff url(images/dolphin_bg.gif) repeat-x bottom left;
padding:0 0 0 20px;}

#dolphinnav ul{margin:0;padding:0;list-style-type:none;width:auto;float:left;}

#dolphinnav ul li{display:block;float:left;margin:0 1px;}

#dolphinnav ul li a{display:block;float:left;color:#EAF3F8;text-decoration:none;
padding:0 0 0 20px;height:33px;}

#dolphinnav ul li a span{padding:12px 20px 0 0;height:21px;float:left;}

#dolphinnav ul li a:hover{color:#fff;
background:transparent url(images/dolphin_bg-OVER.gif) repeat-x bottom left;}

#dolphinnav ul li a:hover span{display:block;width:auto;cursor:pointer;}

#dolphinnav ul li a.current,#dolphinnav ul li a.current:hover{color:#fff;
background:#1D6893 url(images/dolphin_left-ON.gif) no-repeat top left;line-height:275%;}

#dolphinnav ul li a.current span{display:block;padding:0 20px 0 0;width:auto;
background:#1D6893 url(images/dolphin_right-ON.gif) no-repeat top right;height:33px;}

<div id="dolphincontainer">
<div id="dolphinnav">
 <ul>
  <li><a href="" title=""><span>Home</span></a></li>
  <li><a href="" title="" class="current"><span>About Us</span></a></li>
  <li><a href="" title=""><span>Services</span></a></li>
  <li><a href="" title=""><span>Our Work</span></a></li>
  <li><a href="" title=""><span>Contact Us</span></a></li>
 </ul>
</div>
</div>

Images

1. dolphin_left-ON.gif
2. dolphin_bg-ON.gif
3. dolphin_right-ON.gif
4. dolphin_bg-OVER.gif
5. dolphin_bg.gif