a chromeless window is a browser window without any navigation, borders etc. devcon9 provided a zip which contains everything you need:

http://www.6of1.org/chrome.zip

there's always the possibility to show your movie in fullscreen mode, however i wouldn't recommend this. people usually don't like it if they lose the control over their browser. you'll at least have to provide a close button!
here's how to do it:
put this script into the head section of an empty html page, this will only forward to the fullscreen movie:
<script language="javascript">
function newwindow() {
open('movie.html','','fullscreen')
<script>

the opening body tag should look like this:

<body onLoad="newwindow()">

make sure to provide a close button in the movie: "on release -> javascript -> self.close()"