My mpeg-4 movies seem to play in IE with or without the tags that Sparky posted but adding them along with some other tags that my html editor recommends makes IE properly deal with mpeg-4 movies if QuickTime is not installed prompting the surfer to download QuickTime.
This is what I'm now using on my Blog.
Code:
<object classid="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B" codebase="http://www.apple.com/qtactivex/qtplugin.cab" height="310" width="384">
<param name="src" value="http://cleoslinks.com/blogpics/drum-circle-03-21-08.mp4">
<param name="autoplay" value="false">
<param name="controller" value="true">
<embed pluginspage="http://www.apple.com/quicktime/download/" align="right" src="http://cleoslinks.com/blogpics/drum-circle-03-21-08.mp4" type="video/quicktime" autostart="false" controls="console" autoplay="false" controller="true" cache="true">
</object>
Not sure what some of the other param name tags do that Sparky had in his post.