One of the most important principle of the video wiki, is that the original, primary material needed to create great short documentaries should be available to everyone to give each of us the opportunity to remix and improve existing videos.
Also, importantly, the original material should be licensed in a way that is compatible with the licenses that th O TV videos uses. O TV videos are released under the licence Creative Commons, By-SA (Attribute, and Share Alike) 3.0.
Compatible licences are CC-BY-SA, CC-BY, Public Domain.
Commercial use: our aim is to allow commercial TV channels to show our documentary (yes, we hope it will be that good!). Therefore, we have decided to only use material that would allow us to make a commercial use of our production.
Attribution: if you do use some of the material you found, don't forget to properly credit the author if required.
Places to search for original material:
http://www.jamendo.com/ : to find music with a compatible license, check the various lists of albums (by tag, popular, etc), click on the link "Advanced search", then check the box "Find content I can use for commercial purposes."
http://incompetech.com/m/c/royalty-free/ by Kevin MacLeod.