This free app from McGraw Hill is great for elementary school students to work on building their vocabulary. Students can either play on their own or with a partner. Bluster works on rhyming, prefixes & suffixes, synonyms, homophones, adjectives, and over 800 vocabulary words.
This is a great app for elementary aged students. They can practice telling a story by using the visual prompts. It records their narration into the app to play back later.
This is a great article about the evolution of reading. Given the influx of iPads and eReaders into classrooms, the concept of "books" is certainly changing.
This app is free until April, though know that some content becomes an in-app purchase. Bookabi allows students to create their own storybooks with 2D and 3D characters. They can upload their own photos and pictures plus save and share their final projects.
This could be the best $.99 spent on an app. Tools 4 Students includes 25 graphic organizers that can be annotated in the app and then shared via email.
This list comes from Teacher Reboot Camp. The suggested apps provide multiple ways for students to interact with various aspects of stories: plot, characters, setting, etc.