iCommunicate. Visual schedules app that allows you to create simple storyboards for students who need extra support completing routines. You can add your own photos and recordings or use the ones included in the library.
soundAMP R Sound amplification app that also has excellent recording capabilities, such as the ability to add bookmarks to long recordings.
iBooks Apple's ebook app with support for PDFs and ePub documents and full compatibility with the VoiceOver screenreader. Also features highlighting, notes, a dictionary and bookmarking.
Percentally A basic counter that automatically converts tallies to percentages. Great for behavior tracking.
Talking Tom Cat for iPad An animated cat that repeats whatever a student says in a funny voice. Great for encouraging non-verbal students and teaching cause and effect.