You are the second person in PA to have posted about zillions of little snails in their lawn. This is not something that I've ever observed, so can't offer any help other than to suggest that you call your local extension office or find a direct contact at Penn State.

Maybe someone else here has some good recommendations, other than to spread lots of toxic slug and snail killer all over the place.

I've lived in this area my whole life and never saw anything like this before, and in this one development they are all over the place. I figured someone planted a new, exotic plant of some sort and introduced these things to the neighborhood, then they spread to every lawn around by the lawn mowing services that mow 15 lawns on the same street. I hope these things don't become a problem.

Your extension office should be aware of any major trends in the state, which is why I suggested that you give them a call.

I see these little snails periodically on nursery plants, and sure hope that they don't begin a population explosion all over the place.

You might receive an answer from folks at
http://www.carnegiemnh.org/mollusks/palandsnails/contact.htm

Their page says "For information on land snail field collecting, identification, and the ecology of eastern North American species from Virginia north, contact" us.

Oh yes -- then please let us know what you find out.

Here is a link that might be useful: ID help for snails of Eastern US

Contact your local Pennsylvania State University USDA Cooperative Extension Service and ask them.

Here is a link that might be useful: PSUCES