This is your peach leaf:
This is your peach leaf on drugs (Not really.... but it looks really gross):
This is Peach Leaf Curl. Ugly. It's caused by a fungus and if it's really bad, can cause defoliation and a decrease in fruit production. I've picked off all the affected leaves and have put them in the city green waste can. They compost at a really high level of heat, so I am sure that will take care of the fungus. I'll spray my little tree in the winter with a copper spray (yes, it's organic) and see what next year brings!