pagina con form:
codice:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Full featured example</title>


<script type="text/javascript" src="../jscripts/tiny_mce/tiny_mce.js"></script>
<script type="text/javascript">
    tinyMCE.init({
        // General options
        mode : "textareas",
        theme : "advanced",
        plugins : "safari,pagebreak,style,layer,table,save,advhr,advimage,advlink,emotions,iespell,inlinepopups,insertdatetime,preview,media,searchreplace,print,contextmenu,paste,directionality,fullscreen,noneditable,visualchars,nonbreaking,xhtmlxtras,template",

        // Theme options
        theme_advanced_buttons1 : "save,newdocument,|,bold,italic,underline,strikethrough,|,justifyleft,justifycenter,justifyright,justifyfull,styleselect,formatselect,fontselect,fontsizeselect",
        theme_advanced_buttons2 : "cut,copy,paste,pastetext,pasteword,|,search,replace,|,bullist,numlist,|,outdent,indent,blockquote,|,undo,redo,|,link,unlink,anchor,image,cleanup,help,code,|,insertdate,inserttime,preview,|,forecolor,backcolor",
        theme_advanced_buttons3 : "tablecontrols,|,hr,removeformat,visualaid,|,sub,sup,|,charmap,emotions,iespell,media,advhr,|,print,|,ltr,rtl,|,fullscreen",
        theme_advanced_buttons4 : "insertlayer,moveforward,movebackward,absolute,|,styleprops,|,cite,abbr,acronym,del,ins,attribs,|,visualchars,nonbreaking,template,pagebreak",
        theme_advanced_toolbar_location : "top",
        theme_advanced_toolbar_align : "left",
        theme_advanced_statusbar_location : "bottom",
        theme_advanced_resizing : true,

        // Example content CSS (should be your site CSS)
        content_css : "css/content.css",

        // Drop lists for link/image/media/template dialogs
        template_external_list_url : "lists/template_list.js",
        external_link_list_url : "lists/link_list.js",
        external_image_list_url : "lists/image_list.js",
        media_external_list_url : "lists/media_list.js",

        // Replace values for the template plugin
        template_replace_values : {
            username : "Some User",
            staffid : "991234"
        }
    });
</script>


</head>
<body>

<form method="post" action="miapagina.php">

    
    <textarea id="elm1" name="elm1" rows="15" cols="80" style="width: 80%">
        &lt;p&gt;
        &lt;img src="media/logo.jpg" alt=" " hspace="5" vspace="5" width="250" height="48" align="right" /&gt;    TinyMCE is a platform independent web based Javascript HTML &lt;strong&gt;WYSIWYG&lt;/strong&gt; editor control released as Open Source under LGPL by Moxiecode Systems AB. It has the ability to convert HTML TEXTAREA fields or other HTML elements to editor instances. TinyMCE is very easy to integrate into other Content Management Systems.
        &lt;/p&gt;
        &lt;p&gt;
        We recommend &lt;a href="http://www.getfirefox.com" target="_blank"&gt;Firefox&lt;/a&gt; and &lt;a href="http://www.google.com" target="_blank"&gt;Google&lt;/a&gt; &lt;br /&gt;
        &lt;/p&gt;
    </textarea>

    <div>
    </div>

    

    <input type="submit" name="save" value="Submit" />
    <input type="reset" name="reset" value="Reset" />
</form>

</body>
</html>
miapagina.php
codice:
$nome_file = 'posta.html';
$pre = 'qui ci metti tutto quello che vuoi salvare prima del dato ricevuto da tinymce, ad esempio head della pagina ecc';
$post = 'qui ci metti la chiusura di body html ecc';

$h = fopen($nome_file, 'w');
fwrite($h, $pre.$_POST['elm1'].$post);
fclose($h);
non l'ho provato, ma questo dovrebbe funzionare, se il file posta.html non deve andare nella stessa directory di miapagina.php nel nome_file nella prima riga aggiungi il percorso.

Questo codice sovrascrive ogni volta la pagina posta.html.