Youtube Virtuemart Plugin answers your question on how to embed an Youtube video into a product description page. Even there are some ways to hack Virtuemart core files, or to install another Youtube plugin, none of solutions save your time or help you update an Youtube video on your site easily.
For this Youtube plugin Virtuemart extension, all you need to to is to install the plugin normally like a Joomla plugin then simply copy and paste a Youtube link into a product description. It doesn't require you to be hacking. The Virtuemart extension is compatible with all Virtuemart versions and works in custom fields of Virtuemart
How to install Virtuemart Youtube plugin for use?
Step 1: Download the plugin and install it like a Joomla installation
Step 2: Enable the plugin in Joomla administration
Step 3: Go to Virtuemart -> Products -> Custom Field -> Create a new field and give it a name as “Youtube” -> choose Youtube plugin in the section “Selet a plugin” -> Save.
From Step 1 to 3: Your installation and configuration are at once. You don’t need to perform them again.
Step 4: Go to a product -> Custom Field -> Here, you choose Youtube from the Custom Field list -> Copy Youtube URL -> Type the title -> Adjust the width and height for Youtube video if it’s necessary -> Save.
Youtube video will be displayed on the product description page.
Installation Service: http://cmsmart.net/services/joomla-virtuemart-extension-installation