Soak kernels for 8-12 hours and then rinse and drain every 8-12 hours until you've got your desired degree of sprouting. Your results will probably be better with popcorn from the Sprout People or an heirloom variety such as the crimson kernels from Napa's Rancho Gordo rather than a mass market brand. For us, three days of rinsing and draining yielded the most pleasing flavor and texture. It was a pliable reward for risking dental work during so many years of enjoying eating unpopped kernels, but we even enjoyed how the proto-shoots tasted after the first 24 hours. This can all be done using our own containers, but we don't regret ordering the Easy Sprout kit ($13.85), which can pretty much sprout anything, from the Sprout People.
Once the popcorn shoots get going, they can be planted and harvested after they grow to about two inches. They can still be eaten raw at this point or blanched and tossed into hot or cold dishes for an intense burst of sweet crunch. Mature shoots are popping up in restaurants as far away as New Zealand, and we hope it is a future ingredient that Bay Area chefs will play with in their dishes. But maybe the chefs have the same problem that we do: We love the just-sprouted kernels so much that we haven't had enough patience to plant them yet.