Here are some sources for autism apps. It's Autism Awareness Month so there are a lot of apps that are discounted or free.
In honor of Autism Awareness Month, the software developers at Kindergarten.com have made all their educational apps free. It's quite a collection and includes apps focused on speech and language, self-care skills and receptive and expressive identification.
And here's another list of apps to check out.
http://autismandtheipad.blogspot.com/2012/04/april-is-autism-awareness-month.html