The best way that I have found to do this is to use a simple javascript script
SWFObject.
Your HTML code should be changed to:
HTML Code:
<head>
<script type="text/javascript" src="swfobject.js"></script>
<script type="text/javascript">
swfobject.embedSWF("myContent.swf", "myContent", "300", "120", "9.0.0");
</script>
</head>
<body>
<div id="myContent">
<p>Alternative content</p>
</div>
</body>
The alternative content will be picked up by text only browsers and browsers that can't handle Flash and Javascript.
From an seo viewpoint the Alternative text will be picked up by search engines.
Regards
Bob