I was thinking about that issue..
and don't worry, I am almost finished with a simple auth system that can protect anypage you want

but however, if you want to allow users to register, I suggest looking for an advanced sysetm ,since mine will be very simple and will allow the adminstartor to add accounts manually only!
the name is Simple Auth and it's almost finished

btw, I've noticed you've allowed script formatting! which caused duplication of <html><head><body> tags! you may want to disable script formatting to off
look what you currently have:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Anthony, Jane & Katies family website</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link rel='stylesheet' href='layoutw.css' type='text/css'></head>
<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td id="toprow">
<h1>Anthony, Jane & Katie's website</h1>
<div class="button"><a href="index.php?inc=cont">Contact</a></div><div class="button"><a href="index.php">Home</a></div><div class="button"><a href="index.php?inc=info">Information</a></div><div class="button"><a href="index.php?inc=photo">Photos</a></div><div class="button"><a href="index.php?inc=vid">Videos</a></div><div class ='button'>
<a href='index.php?inc=photo1'>View photos</a>
<a href='index.php?inc=photo2'>Upload photos</a>
</div>
</td>
</tr>
<tr>
<td id="maincontent">
<div class="pagetext">
HERE HERE HERE
<HTML>
<HEAD>
<TITLE>Simplicity oF Upload 1.0</TITLE>
<STYLE type="text/CSS">
<!--
body {
font-family: Tahoma, verdana; font-size: 12px;
}
p.header {
font-family: Tahoma, verdana; font-size: 18px;
}
a:link, a:visited {
color: #009999; text-decoration:none;
}
a:active {
color: #FF6600; text-decoration:none;
}
-->
</STYLE>
</HEAD>
<BODY>
HERE HERE HERE
<p align="center" class="header">Simplicity oF Upload 1.0 Beta 4</p><p align="center">
<form method="POST" enctype="multipart/form-data" action="/index.php?inc=photo2"><input type="file" name="SFUfile[]" size="20" /><br />
<input type="file" name="SFUfile[]" size="20" /><br />