I've had clients post work I've narrated on Youtube and have some links to their work on my web site. If you can edit video on your computer, you could probably make a "still" graphic with your name and logo on it while the demo is playing. Although I would think serious clients would probably prefer an mp3. <g>
I used to put out a yearly Christmas video for friends and family and was convinced to start putting it on Youtube.
Here is a clip of a story I did of narrating a presentation for a local school system.
Youtube is fantastic fun!