Any question answered...

Er, yes. But I want the frame embedded in a forum post, not as an external link.

You can get the HTML to publish it, but obviously PHPBB forums don't allow HTML code in the posts and running [code] or any other tags around it doesn't work.

For good reason - HTML embeds are generally meant for pages you host yourself, or your own blog. Allowing HTML to be inserted into BB posts by users is a vast security hole.

[code] tags are generally meant for displaying code in a post without the browser interpreting it as actual code to be rendered.