I did some searching online and had a hard time finding the exact spider but I believe it is some kind of wolf spider. I could not find any for sure information about what the exact species is, but from what I could find, I believe it is a hogna helluo wolf spider.
Here are some interesting things I learned about wolf spiders in my search for this cool guy:
Wolf spiders do not build webs instead they stalk their prey.
Here is a crazy one. They actually have 8 eyes! Four very small ones across the front, two large ones behind that and and then two medium ones behind the large ones. Since they do not build webs they use their excellent sight to hunt for prey.
Males do not live for more than a year but females may live for about 3 years.
I read that if they get enough of food they can produce several clutches of eggs each year. So I say get eating spiders!
Another interesting thing is males perform courtship displays by waving around their legs to attract the females.
I almost picked one of these guys up the other day and good thing I didn't because I found out that they do bite and have venom also. Although it is not enough to kill a person, but from what I read it can hurt pretty good.
One site that I came across said that you can shine a flashlight around at night and the wolf spiders eyes will shine in the light (kind of like frogs I am assuming). I will have to try this some time soon. If it does work it would be cool just so see how many spiders I have handing around out at the farm.
Here is a cool site that I came across, it shows picture of all the beneficial bugs and tells about them, good page. http://upnorthfarm.wordpress.com/beneficial-insects/