The Vermont Agency of Natural Resources just announced a free Vermont State Parks App:
http://itunes.apple.com/us/app/oh-ranger!-parkfinder-vermont/id509618668?mt=8
As Parks Passes start to go out, this would be a wonderful thing to promote with the passes for library members with smart phones and tablets.
It might even be a great time to promote certain apps that have to do with the great outdoors, like the Audubon Guide Apps, which are a little pricy but I use them all the time myself and that purchase supports local business (Green Mountain Digital).
http://www.greenmountaindigital.com/
What are your favorite reference apps that you tell patrons about?