Based on your description, your neighbor's trees are females. Female trees have three to five leaf-clusters per leaf-stem, whereas, male trees only have one leaf per-leaf stem; female trees are the only ones that bear fruit...males produce pollen, not fruit.

garland, Check out the UC-Davis Fruit & Nuts Research Center website, and the California Rare Fruit Growers' website(they also deal with stuff that's not 'rare'). Lots of info there, as well as contacts who can direct you to sources - &/or tell you what will or will not work in your area. Years ago, I was interested in pistachios, too; but Dr. Louise Ferguson at the UC-D F&NRC told me that they wouldn't work here in the hot, humid Southeast. I tried a few P.vera seedlings anyway - and she was right.

i seriously did not think pistachio trees could grow on long island. the wet temperate climate is so different than hot deserts(?) climate... but the tree was doing very well. (Not wild, but in a local gardens, therefore labelled.) anyways, when could i expect to find nuts?

The answer is yes. If you go to Photobucket/ChristianWarlock you can see methods on growing trees in 5 gallon buckets to maturity. I grow everything from seed. I grow Cashew, Citrus, and have Macadamia seed on order. The method is called Sustainable Hydroponics.