For a decent video site you're probably going to need to know how to do video in Flash, how to use XML, PHP, how to code in XHTML and how to style with CSS.
Start by learning the XHTML and CSS. Use
Coda or
TextEdit/
TextMate for your code, and
Photoshop and
Illustrator for your images and layout.
However, you might consider going into a less saturated market. Video sites are everywhere.
YouTube - Broadcast Yourself.
Google Video
Vimeo, Video Sharing For You
The idea has been done to death, and done well. Maybe you would be better to focus your efforts on a more original project.
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