I agree with @Abe Miessler's diagnosis of peach leaf curl. Last year one of my peach trees had a bad case of this -- the other one 30' away was mostly unaffected. (One of the recommendations for prevention is to plant resistant varieties.)
I'm not sure where I read this, but once you've got it, you can't cure it this season -- you can only prevent it next season.
The Organic Gardener's Handbook of Natural Pest and Disease Control (Bradley et al) describes peach leaf curl on p. 324:
- Plant resistant cultivars.
- Remove and destroy infected leaves.
That reference says it's worst in cold, wet springs. You can apply a preventive spray of lime sulfur (calcium polysulfide) (or "Bordeaux Mixture" -- a copper spray) either in the fall after leaf drop or in the spring before bud break. (See The Backyard Orchardist (Otto), p197.) Beware that copper-based sprays are toxic to fish and earthworms (at least), so don't overdo it. Beware that sulfur sprays can be toxic to the plants in hot, dry weather (see links below). Either of these sprays are fairly generic items that should be available at a well-stocked garden center or nursery.
It may not be practical advice for you at this point, but Handbook also suggests growing dwarf trees in pots where they won't be cold and wet in spring and then moving the pots outside for the summer.
Some other info: