0^0 is a can of worms; Stavros and I chatted about it awhile ago with no
resolution.
To understand some of the issues, you might like to start with
http://mathforum.org/dr.math/faq/faq.0.to.0.power.html
I proposed a new Maxima function, call it pow, such that pow(x,0)
evaluates
to 1 for all real or complex numbers x. Such a function would be useful
inside summations, where we generally _do_ want 0^0 to evaluate to 1.
Barton