I need to play an flv in streaming in a website build on a php/apache2/mysql CMS. I like a lot http://www.visionstreetwear.com website and i would like to use this layout with a flv as header.
I believe you can't do 'true' flash video streaming without paying for streaming service from the hosting provider.
If you don't have that, you can alternatively do 'progressive streaming' of the flv file. See this article on Adobe website about how to create flash file that can do it.
What I have done before, is to create a swf file that works as a container for video which contains some actionscript to play external video file, store video on the web server, then feed external data to tell swf which movie file to play and where the movie file is located.