The correct HTML is the <object> tag. I believe the <embed> tag was created by Netscape developers before the standard, but don't quote me on that. It's suggested that you provide both, but no one uses Netscape any more, so you only really need the <object> tag. The W3C seem to think so, anyway.
<object width="{width}" height="{height}">
<param name="movie" value="{filename}.swf">
</object>