There are several ways of promoting both audio and video marketing ideas. If you would like to promote your ideas or programs via the audio visual route then this will be fine.
There are marketers who already have broadcasts or even regularly do broadcasts on the internet. One of the most obvious ones is the webinar.
You may not wish to do this sort of event to start out with so why not do a podcast or make a youtube video. Both are relatively simple to do.
Perhaps you just want to do something a little bit differently from the way you have seen it done before.
If you are camera shy this is no problem. You don't have to appear on the video yourself. Just put a commentary to something you are doing on the internet. Show the way you do something in particular.
There are some people who only do podcasts. With all these methods you want to gain traffic, so you want to use as many marketing methods as work successfully for you.
There are several free programs you can use to start off with and then as you progress and need more features you can go on to some of the paid programs.