serving video file

Question

Dear all,
I am assigned to a project where I have to develop a web service which will serve client with different video files according to some certain criteria of the client. A large number of video files will be stored in the web server for this purpose and in the client end a C# application will be used for watching the sent video.
I am a newbie. I have basic idea on designing webservice and consume them from client end. But I've never dealt with video stuffs. Please give me an insight on how can I start designing this project. Also please refer me some useful articles regarding this. I have to design both the server and client end softwares.
with thanks