There are several sleep-away camps for kids with special needs in my state. I got a list of them from the developmental disabilities agency web site. Also, you might ask parents of other kids in your area where they send their special kids to camp. Here's a web site I found that might help:
http://www.kidscamps.com/special_needs/autism.htmlIs there a special needs email group in your state? I know some of the major disability groups such as The Arc and the Epilepsy Foundation know about camps for kids with developmental disabilities. Some even allow siblings to go, too!