Actually, We have those here too. They're one of the most common garden spiders, that you see feeding on mantids, butterfly's, etc. They're harmless to humans, but are fairly defensive. Poke at them and they'll poke backMost of the time you can see them in fields around patches of sun, by tree's and such. They're one of the most gorgeous spiders we have!!!
Here's a link...
http://en.wikipedia.org/wiki/Yellow_garden_spider