I have theese near my house. I did some research and I think I remember reading that they originated in Australia, but now they can be found in some parts of the US. That info may be totally wrong, however.
This photo was taken in the morning, at a friends house, in Dallas Texas. I saw the spider between some crepe myrtle trunks and thought it was the wildest one I have ever seen. It was about the width of a nickle.