Never mind — I figured it out — easy of course, once I could figure out where to put it!
<?php
/*
Plugin Name: You Tube Embed
Plugin URI: <none yet>
Description: Adds quicktags for embedding youtube videos in your blog
Version: 1.0
Author: Notwen
Author URI: <none yet>
*/
/*
Drop in your /wp-content/plugins/
Activate the plug-in via admin
*/
add_filter('the_content', 'notwen_yte');
function notwen_yte($post_content)
{
$pattern ='@<yte>(.*?)</yte>@';
$replace = '<object width="425" height="350"><param name="movie" value="https://www.youtube.com/v/$1"></param><embed src="https://www.youtube.com/v/$1" type="application/x-shockwave-flash" width="425" height="350"></embed></object>';
return preg_replace ($pattern, $replace, $post_content);
}
?>