Can You Help ID this Spider? (pictures)

Question

I've found these things numerously in my yard while I'm doing work. maybe 5 or 6 a day.

I put a dum-dum pop in the picture for scale.

Just tell me if it bites...if it's poisonous or not. I've been killing them just to be safe. But if it's harmless I'll leave them alone.

They spin HUGE webs.

All of them have a black hourglass on the underside.

Most of them are brown, slightly hairy....some of reddish-brown like in the pictures.

http://i115.photobucket.com/albums/n311/LaRueDeeko/0812081513.jpg

http://i115.photobucket.com/albums/n311/LaRueDeeko/0812081514.jpg

http://i115.photobucket.com/albums/n311/LaRueDeeko/0812081514a.jpg

http://i115.photobucket.com/albums/n311/LaRueDeeko/0812081517.jpg

Answer 1

Definitely a garden orb weaver. They grow large. Their bites are not painful or harmful. They grow very large and eat thousands of flies. All spiders bite. Given that dark coloring, we can assume it was going to molt very soon, and get a lot bigger. Stop The Killing.

Answer 2

They look like your typical orb weaver spider.