css drop down menu , help please

[afallingpanda]

<table cellspacing=0 cellpadding=0 class="headertable">

<tr>

<td  class="navbar"><a href="index.php">Home</a></td>

<td  class="navbar"><ul class="drophead">

<li><a href="">Businesses</a></li>

<ul>

<?php

 

$myquery = sql_query("SELECT objectid, object_title FROM webmanage_objects WHERE parentid=6226 AND archived=0 AND is_visible=1 AND object_type='Organisation' ORDER BY object_title");

 

while ($myrow = sql_fetch_assoc($myquery)) { 

print"<li class=\"dropdown\">";

 

transfer_row($myrow);

print "<a href=\"../businesses.php?id=$row_objectid\">$row_object_title</a>";

 

print"</li>";

}

print"</td>";

?>

 

<td  class="navbar"><a href="gallery.php">Gallery</a></td>

<td  class="navbar"><a href="contact_us.php">Contact Us</a></td>

</tr>

 

</table>

</div>

 

 

thats my code for the navbar, and heres the code for the css dropdown that i have created:

 

.drophead { 
    position: relative;
    top: 0px;
    left: 0px;
}


.drophead ul { 
    position: absolute;
    top:17px;
    width:200px;
    display: none;
    border:1px solid #0B3B0B;
    background-color:#B4C4B0;
    text-align:left;
}


.drophead ul li a{
    display:block;
    border-top:1px solid #8C9A89;
}


.drophead ul li a:hover{
    border-bottom:none;
    background-color:#A5C39E;
    padding-bottom:0px;
}


.drophead:hover ul { 
    display: block;
}

i was wondering if someone could tell me how to add a cool transition to it, so the list shows with some animation.

thanks