Loading module to a templated page
I don't know if it's a paste-issue, but you should intent your code ;)

You are building the file-path twice. You should move that line:

$mod = 'modules/'.$module.'.tpl';


To the begining of the function (and give it a better name):

public function LoadModule($module,$position)
{

    $absTemplatePath = 'modules/'.$module.'.tpl';
    if(file_exists($absTemplatePath ))
    {


That Line:

LOGIT('$module - module not found.');


should be (else $module wouldn't get replaced):

LOGIT("$module - module not found");


If the template file does not include php-code you should use file_get_contents instead of ob_start, include, ob_get_clean (performance-wise). If you do have php-code in your templates, you might have a look at zend-framework's Zend_View.