You can also take them to your LFS, some places will take them and sell them as loach treats, or they'll just turn them loose in with their loaches or other aggressive fish.
My housemate has a tank full of large rainbows, leporinus, catfish, etc. I just vacuum my extra pond snails every month or so and put 30 or so in that tank, they get eaten in a day or two.
If you overfeed, they'll eventually reproduce to crazy amounts. Since many of us breed and have good reasons for overfeeding, there's not a great way to regulate except use the extra as feeders.
I don't recommend releasing them into the wild. It's a bad idea to get in the habit of transporting species across state/country boundaries, then releasing them in the wild, you could inadvertently starve out a local species or release a predator on a plant and cause a serious change to the ecosystem that you can't recover later.
