try the following examples.
SWFObject embed by Geoff Stearns (full page) @ deconcept
(will take a min or so to show boxes of colours or will show you a message straight away about needing to upgrade your flash player)
Harris's Blog: New and improved Grace - now with walk alone feature!
the first is a JS example of embedding flash content. The second is a you tube video embedded with no JS. The examples are odd but it is late and they are the first things I thought of that would serve the purpose.
In firefox, go to tools -> options then click the content tab. Make sure javascript is on.