Hi Robert Williams,
Thank you for using our services.
Since Sitefinity 3.6 we do have video library built in. You can create video libraries, which support .wmv format and then upload .wmv videos tho those libraries, and we do have a Video control. If you want to achieve this using .wmv videos it is already built in. If you wish to use different types of videos, you can add more video extensions to the video library type and substitute the silverlight player control on the template for playing videos with some other, this forum thread
might come handy for that purpose.
the Telerik team