HTTP is the oldest protocol on the web and therefore it is understood by all PCs connected to the Internet and video also fits in there. All you need is the correct tool.
1AVStreamer is one of the tools out there that is capable of streaming a HTTP real-time live video stream.
With 1AVStreamer you can stream http transcoded or pure and for transcoding several options are available.
Whatch the video bellow to understand how it is done.