It's an argiope, a common orb-weaver.

Not a problem for people, pets, or kids.

It is the queintessential Garden Spider. a.k.a. "writing spider" in some parts of the south. An old local fable I used to hear was "It means good luck if you find one among the plants in your garden". That might have something to do with the name Garden Spider. I have also been told that the nickname "writing spider" is due to the zigzag pattern of silk in the center of the web.