This is a striped down version of what I use:
HTML Code:
<script src="/path/to/vbroot/clientscript/md5.js" type="text/javascript"></script>
<form action="/path/to/vbroot/login.php" method="post" onsubmit="md5hash(vb_login_password,vb_login_md5password)">
<input name="vb_login_md5password" type="hidden" />
<input name="s" type="hidden" value="" />
<input name="do" type="hidden" value="login" />
<input class="bginput" name="vb_login_username" size="12" type="text" /><br />
<input class="bginput" name="vb_login_password" size="12" type="password" /><br />
<input checked="checked" class="bginput" name="cookieuser" id="cb_cookieuser" type="checkbox" value="1" /><span class="smallfont">Use Cookies</span>
<input class="button" type="submit" value="Login!" />
</form>