Basic Video Info

Hi
I'm getting lost in the basics here. I produce video. I
would like to view my videos over the net. I've downloaded
Windows Media Encoder. For raw .avi's I get a message
telling me that I require a codec. For Window's .avi's the
encoder works but gives me a black frame every half
second. It's like I'm using a demo version, but I can't
find where to get the real thing. Can someone please fill
me in?

Thanks