I put the peaches into hot water for a few minutes until their skins are loose. The water is steaming but not boiling. About five minutes is usually enough.
Once I pull them out, I take off the skins quickly to help them cool more quickly. After a few minutes, when they are cool enough to handle, I pit them and cut the flesh into pieces.
I then put them into a plastic bag along with a little sugar to absorb the peaches' water. I can freeze the bag until I have a little more time to cook and can the preserves.