rocknbil - 4:40 pm on Aug 21, 2009 (gmt 0)

Have you looked at SWFObject?

SWFObject is a way of incorporating Flash that first places the alternate content, then if scripting and Flash are enabled writes to the static div/element to display the Flash. No noscript tags are required. Your document looks something like

<div id="flash-placeholder"><img src="alternate-content.jpg"></div>

And if JS/Flash is enabled, it writes to "flash-placeholder." Cross browser compatible, progressive enhancement, SEO friendly, it's pretty much . . . perfect.

And it's open source [code.google.com]