I saw this question posed on on the forums at AnandTech.com and would love to see if it is plausible.
 
"Ok, here is the deal. I have a freind that lives about 5.7 miles away from me and almost has a line of sight. He would probably have to put an antenae on his house to get a line of sight to mine. At my house, I have no options for high speed internet access, at all, but at his house, he can get cable. I got to thinking, and I came up with an idea. What if I could get ahold of some wireless networking equipment that I could use to network to his house, then he could get cable, we could split the monthly bill, and I would have cable access at my house.

Here is my question: What equipment could I use to do this? I found some stuff on cisco's site, but it costs about $8000. The speed does not have to be supper fast, but I would like to have something at least the speed of ISDN.

I want to know what other people have to say abhout this, so shoot. "
 
Is this plausible.  Is there any technology out there that uses public spectrum over a 6 mile distance ?