You should be able to span that distance with a directional 802.11b network that operates at 2.4 Ghz.

Here is an example of what someone did with an old PrimeStar dish. It's a little bit technically challenging, but not out of reason.

http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

For 1500 feet, you may be able to get by with just the juice can feed horns at each end.

I'd say you can make this work if the two houses are line-of-site and that means no trees. You also need to minimize the length of the feedline - the best solution is to mount the wireless access point outside at the antenna as shown by one of the links at the bottom of the page referenced above. However, that example does not use proper waterproofing and the method of feeding the signal into the juice can is not good.

Ken300D