You could either pick them out by hand/destroy egg sacs, use the lettuce method (weigh some lettuce down with a rock before turning off the lights, then remove the lettuce the next morning, similar to what guppymonkey suggested), or simply not overfeed the tank.
If you are careful about how much you feed your fish, you will most likely not experience a population explosion. Common snails in fact I've found make decent scavengers.