The Tutpup website allows the students to study spelling and compete with other students around the web. Spelling is a subject that can always use support.
Learning Games for Kids would be great for keyboarding skills. I don't think we put enough emphasis on keyboarding in the elementary grades. The kids could work at their own pace and sharpen their skills.
One of the apps I liked was ABC Cursive Writing Lite. The kids practice cursive on the Ipad. Cursive writing is laborious for many students. Even if students do not write in cursive they will need to be able to read it and understand it at some time. Also, the student can access google docs and work on projects at home and school.
As far as management of the devices, I will have schedule and sign in (nothing elaborate). I will appoint a couple of students to help me monitor the use of the devices. They will also be able to help students when needed.