The Victorian Department of Education and Early Childhood Development has a very useful resource 'Ipads in Special Education'. This is a comprehensive document listing hundreds of educational apps by category as well as providing information on the accessibility funtions of the iPad. (Prices of the Apps are not included)
Apple has a Special Education section in the iTunes App store listing a range of Apps with their prices.
Visit Apples webpage explaining the accessibility features of the iPad for:
Apps for people with Autism.
Slideshow: iPossibilities: iPods and iPads in Special Education. 3 slideshows looking at various apps for special needs education.
Jeremy Browns App recommendation for students with Autism.