When preserving food, always buy the best quality of produce. Wait until the peaches are ripe. Clean the peaches, I usually do small batches of about 18 peaches at a time.
To make peeling the peaches easier, score a shallow "X" on the bottom of each peach with a knife. Fill a large pot about 3/4 full of water and bring to a boil. Prepare a large bowl of ice water and place paper towels handy.
Gently submerge the cleaned peaches (I usually do about 5-6 at a time) into the boiling water for about 30-60 seconds. The more ripe the peaches are, the less time it takes. I leave ripe peaches in the water for 30 seconds. Transfer the peaches immediately into ice water. Leave in the ice water for about 1 minute. Using a slotted spoon, remove the peaches from the ice water and place on paper towels, pat dry.
The peach skins should slip off easily. Cut the peaches in half, remove the pit and slice them in the size you want. You will need to treat them to prevent browning. One way is to slice the fruit into large bowl containing 1 gallon of water mixed with 3000 mg ascorbic acid (which is 6 crushed 500 mg vitamin C tablets or 1 teaspoon Fruit Fresh). You can also sprinkle about 1/2 teaspoon of the Fruit Fresh per quart over the fruit, right before you add the sugar to the fruit.
When you have peeled and treated the peaches, drain the water. Place peaches in large bowl and add 1/2 cup sugar for each quart of peaches. Stir gently and let the fruit stand for 15 minutes. The peaches will begin to make their own juice. During this time, you can label the bags or containers you want to use to freeze the peaches.
Pack the peaches into freezer bags to within 3-4 inches of the top. Squeeze out the air, seal and freeze. If using plastic containers, leave about 1 inch of headspace before freezing.
If you plan to serve your fresh peaches within a few hours, you can place them in a marinade of orange juice or lemon water to keep them from darkening.