TheJones - 3:03 pm on Jan 6, 2009 (gmt 0) Hope this helps.
Well you need to shoot the video with a blue/green screen and then key out that color. Like most effects it's all in the prep. If you have a well lit green screened video it's very simple, if not it can be a nightmare. Programs like After Effects offer decent keying, but there are programs that are made for this purpose and do it quite better. After you get the video bg keyed out you need to render it as an FLV to preserve the alpha in flash. You can then import the FLV as an embeded movie into flash and work it like a normal swf, or stream it from a media server, and so on.
Hope this helps.