ideas sketch is a brainstorming FREE app it is similar to the app Popplet . It is very easy to use and could be used in a multitude of ways in the classroom. This app allows you to mind map your ideas using text. If you like the app you can upgrade to the paid version which gives you more features. I think the ability to add photos would be good (although this may be added at a later stage).
Ideas for the classroom
1. Use the app in the planning stage of the writing process with the students. The students could plan their writing, this planning could stay on the ipad or take a screen shot and print the page.
2. Create a class mind map on a topic to asses what the children already know and gather ideas.
3. Create a mind map on themselves
4. Create a concept map on a topic
5. Create a story map using key words (sequencing).