I recently worked through this and came up
with an ASP.NET C#-based solution that worked for the following browsers
(tested on XP): Internet Explorer 7, Firefox 3.0.10, Opera 9.64, Safari
4.0, Google Chrome 2.0 and Flock 2.5.
What it comes down to is writing a bit of server-side C# to generate
one object tag syntax for IE and another one for "everyone else".
Here's a link to the full post with ASP.NET/C# source code and a live example:
http://mikeknowles.com/blog/2009/06/16/MultipleBrowserWindowsMediaPlayerObjectTag.aspx