Barry, the easiest - onsite - solution is to buy it (I am not affiliated in any manner):
EasyFLV. Note: by converting to flv one utilises visitors Flash players to show the video.
Otherwise host the videos on a specialist video hosting site (ala YouTube but without being UGC open content) and let them deal with the technical fun and games. Then you need only link or offer an embedded player.
And there are several handcoding options depending on whether you want download then play or streaming, leveraging Flash or direct, etc.
Always when offering video:
Caution:
* consider the potential traffic and bandwidth.
* consider whether a FFmeg host or other dedicated streaming server might be required.
* consider your hosting fine print and then get specific questions answered in writing: there is no such thing as free lunch or unlimited bandwidth.
--You do know that some folks are now experimenting with embedded video in emails?
Spam that wiggles jiggles and moans...
And media players that won't shut off...As to your vids being 'stolen' it is pretty much like your images, if they can see it, it is on their machine and they can swipe it. But then that is what is already happening on YouTube et al.
Depending on format and delivery one can make things more difficult, one can add tags to auto-identify one's stuff elsewhere, etc. but stop it? No.