Can a video or audio tape serve as a legal will?

Not to my knowledge. Wills must be drawn in a particular way and executed in a specific manner for them to be accepted as a "Will". This is particularly the case with what are known as "holographic Wills" which are handwritten Wills. They are not allowed, except when the writer of the Will is in the Armed Services and under specific conditions such as in a theater of war at the time. Otherwise, there are very few ways you can make a legitimate acceptable Will. There are a few more exceptions, such as if a person is about to die at the time and is unable to get their Will done normally, but I have seen no movement yet on using a videotaped Will for that purpose. By the way, I think its a great idea since I videotape all my clients' Will signings to stave off Will contests which can be very costly. This is just an added benefit of videotaping the actual signing to prove there was no coersion or force being used to get it signed. Good luck.