Toast pickling spice and crushed red pepper in a dry medium saucepan over high heat until fragrant, about 30 seconds. Add water, vinegar, sugar, and salt and bring to a simmer, stirring to dissolve sugar. Add peaches and simmer just until tender, about 20 minutes. Remove peaches from liquid with a slotted spoon, reserving liquid, and set aside just until fruit is cool enough to touch.
Pinch the skin from peaches-if the skin pulls off easily-and discard. (If the skins cling, don't fret-the peaches will be beautiful and tasty that way as well.) Transfer peaches to a sealed container, cover with the reserved liquid, and refrigerate for at least 24 hours. The peaches will keep for 1 week tightly sealed in the refrigerator.
From Food Network Kitchens Get Grilling, Meredith Books, 2005