Well, HTML5 is still in development and there is no standard per say and IE has only added support to it in IE9, that too it does not ship the codes, you need to download them. Basically you will need to convert your .swf to .ogg(for FF and Chrome) and .mp4 (for Apple).
Then, add code which allows flash fall back for IE.
Below is the code
<video id="movie" width="700" height="467" preload controls> <source src="cassic.ogv" type='video/ogg; codecs="theora, vorbis"' /> <source src="cassic.mp4" /> <object width="700" height="467" type="application/x-shockwave-flash" data="cassic.swf"> <param name="movie" value="cassic.swf" /> <param name="allowfullscreen" value="true" /> <param name="flashvars" value='config={"clip": {"url": "http://www.webcreators.com/wave/cassic.mp4", "autoPlay":false, "autoBuffering":true}}' /> <p>Download video as <a href="pr6.mp4">MP4</a>.</p> </object> </video> <script> var v = document.getElementById("movie"); v.onclick = function() { if (v.paused) { v.play(); } else { v.pause(); } }; </script>