try this ...
HTML Code:
<script type="text/javascript" src="/forums/clientscript/vbulletin_md5.js"></script>
<form name="vblogin" action="/forums/login.php" method="post" onsubmit="md5hash(vb_login_password, vb_login_md5password, vb_login_md5password_utf, 0)">
<table border="0" cellspacing="2" cellpadding="2" class="smallText" style="color: #999DB8">
<tr>
<td valign="top" align="right">username:<br /><input type="text" style="width: 80px;" class="input_login" name="vb_login_username" id="navbar_username" accesskey="u" /></td>
<td valign="top" align="right">password:<br /><input type="password" style="width: 80px;" class="input_login" name="vb_login_password" accesskey="p" /></td>
<td valign="bottom" align="right">
<input class="input_login" type="submit" value="Login" accesskey="s" style="margin-bottom: 2px; padding: 0px; text-align: center;" />
</td>
</tr>
</table>
<input type="hidden" name="cookieuser" value="1" id="cb_cookieuser_navbar" accesskey="c" />
<input type="hidden" name="url" value="<? echo $_SERVER['REQUEST_URI']; ?>" />
<input type="hidden" name="s" value="" />
<input type="hidden" name="do" value="login" />
<input type="hidden" name="vb_login_md5password" />
<input type="hidden" name="vb_login_md5password_utf" />
</form>