Hello, I must say that I can't make up my mind about anything related to SEO, cause there are so many different opinions. But I would be very grateful if someone could help me with the problem I post:
I have a web page where all the navigation points to content that is included in the same html document using the server variable PHP_SELF. That means that the html document, and the title of the document, will remain the same. I use a switch instruction to decide wether to include one or another content.
Now I would like to ask ¿will my content still be indexed by search engines? I know Yahoo differs from Google, and there are probably many differences among search engines. But is it generally a bad practice to do so?
The way the web page is made calls PHP_SELF with different queries, and then includes diverse content based on a switch instruction. The thing is that I can't make up my mind about changing the code so that I use a template (home made, so to say) and use the template to reproduce the contents with the navigation still in place.

The images related to the content also change by means of the switch instruction, like so:

if (isset($_GET['pagina'])){switch ($_GET['pagina'])
{case "tesis":
echo "Imprimimos, encuadernamos y le damos el mejor acabado a tu Tesis";
$titulos[]="Tesis urgentes en menos de 4 horas";
$titulos[]="Tesis con pasta dura o blanda";
$titulos[]="Acabado profesional de tu tesis";
$titulos[]="";
$titulos[]="Encuadernaciones diversas tales como holandesa y mestiza";
$titulos[]="Cubiertas doradas, en serigrafía, grabadas o laminadas";
$titulos[]="Puedes elegir las cubiertas de tu tesis";
$titulos[]="Tesis urgentes con encuadernado térmico";
$titulos[]="Puedes elegir encuadernación con tela, keratol o piel";
break;

etc.
And using the following in the img tag:

<img src="images/<?php $imagen=isset($_GET['pagina'])?($_GET['pagina'])."1".'.jpg':'primera.jpg'; echo $imagen; ?>" alt="Multimagen" width="450" height="225" title="" rel="<h3><?php echo $titulos[0]; ?></h3>"/>

for example.
And the links use the following structure:

<li class="kwick1"><a href="<?php echo $_SERVER['PHP_SELF'];?>?pagina=tesis">Tesis</a></li>

Then on the content div (where I want the different content to appear), it goes:

<?php 
if (!isset($_GET['pagina']) || !$_GET['pagina']) {include_once('main.php');}else{
$paginas_permitidas=array('tesis', 'ploteo', 'impresion', 'varios', 'main', 'contacto', 'ubicacion');
if (isset($_GET['pagina']) && in_array($_GET['pagina'], $paginas_permitidas)) {
include_once($_GET['pagina'].'.php');
}}
?>

¿Am I definitevly off? ¿Does this mean that search engines will not index the content of the web page? I think it's better to include more than one page on the site, no doubt, but that leaves including dynamic content like this out. So can somebody give me a plain answer?