It may look a bit longer with css.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Form</title>
<style type="text/css">
.main{
margin-left:auto;
margin-right:auto;
width:500px;
height:150px;
}
.fields
{
width:170px;
border:solid #CCCCCC 1px;
}
.button
{
width:80px;
background-color:#FFFFFF;
border:none;
display:block;
float:right;
color:#0066CC;
margin-top:30px;
}
.button:hover
{
color:#FF3300;
}
.legend
{
font-family:Arial, Helvetica, sans-serif;
font-size:14px;
color:#FF6600;
}
fieldset
{
width:500px;
}
</style>
</head>
<body>
<div class="main">
<fieldset>
<legend class="legend">Login Details</legend>
<form action="formProcess.php" method="post">
<label style="font-family:Arial, Helvetica, sans-serif; font-size:12px;">Username : <input type="text" name="txtUsername" class="fields" /></label>
<label style="font-family:Arial, Helvetica, sans-serif; font-size:12px; margin-left:10px;">Password : <input type="password" name="txtPassword" class="fields" /></label>
<input type="submit" value="Login" class="button">
</form>
</fieldset>
</div>
</body>
</html>
copy and save it as .html file and check.