The pits contain chemicals which can be converted into cyanide when digested. They are likely to cause digestive distress, and more severe symptoms-- up to and including death if a large quantities are eaten. Stick with almonds.
They are not edible, but can make great jewelry. My father, who was a jewelry maker in his day, took a peach pit and carved out a little basket. He sanded it down to it was soft. It make it look like a wicker basket. He added a few tiny pearls and it was beautiful. It was the best gift I have ever gotten.