So, the first step is to select your peach. If you are picking peaches yourself, choose peaches that have a nice golden color with a "blush" on them (the blush is the pinky part). Peaches will ripen off the tree, so don't hesitate to pick "hard" fruit as long as it isn't green. If purchasing peaches that have already been picked, choose a peach that gives slightly to gentle pressure.
To begin blanching, bring a large pot of water to a boil. While waiting for the boil, make an ice bath (cold water and ice) in a large bowl. If your peaches are ripe to slightly over-ripe, go ahead and dunk them into the boiling water for about a minute or so (don't overcrowd them). Remove the peaches from the water and dunk them in the ice bath. Let them chill for about 30 seconds. If your peaches are still a little firm, make a small X-shaped slit in the bottom of each peach before you blanch them. This will help to loosen the skin.
Remove your peaches from the ice bath and rub them between your hands. This loosens the skin, and you should be able to slip the skins right off. If the skin is still stubborn, it's okay to re-blanch them. Discard of skins.
Pitting the peaches is the next step. Peaches that are ripe have a natural groove that runs vertically around the peach starting at the stem end. If you can find this, simply slip your thumb into that groove and run it along the pit. The first half of the peach should slide right off. Wedge the pit out of the second half and discard the pit (or try growing a tree!). If you can't find this, run a paring knife along the pit vertically around the whole peach (that is, starting and ending at the stem). Most of the time, you'll end up with two perfect peach halves. The rest of the time, you'll end up with mutilated parts of a peach. In this instance, puree up the pulverized peaches and make a lovely Bellini, some fruit leather, or cook up some jam. Because of this, I recommend buying slightly more peaches than you think you'll need :-)