To answer this question is beating a dead horse. But it is summer.
We know the rules of exponents: .
Therefore we would have to allow .
But we never allow division by zero!
Therefore, it can be argued that is not defined.
But if you look at the first link, you will see that this is very old argument.
The great Euler argued that .
Math Forum: Ask Dr. Math FAQ: Zero to Zero Power
Math Forum: Ask Dr. Math FAQ: N to Zero Power