(newbie) Flash->PHP->.txt?

Hi... I'm a longtime Flash developer who is just starting to explore server-side scripting as a means of extending Flash's capabilities. I have a problem which I'm sure is incredibly simple, but I don't have enough knowledge of PHP to figure it out. Inside my flash movie is a user-defined variable ("color"). What I need is a php script that, when a submit button is clicked, will receive the flash variable and write it to a .txt file as color=value. I think I need something along these lines, but I'm really just flailing here... <?php $data="flash.txt"; $fp= fopen($data, "w+"); $fw= fwrite($fp,$color); fclose($fp); ?> Any help would be greatly appreciated... K.