Modeling, including video modeling, is considerd to be an establishned intervention for teaching communication, higher, cognitive functions, personal responsibility, and play to children with autism spectrum disorders (including Asperger's Syndrome) from ages 3 to 18 years.
Source: National Standards Report - http://www.nationalautismcenter.org/nsp/
According to the National Professional Development Center on Autism Spectrum Disorders, video modeling can be considered an evidence-based practice (EBP). This organization indicates that research supports the use of video modeling for young children through middle-school ages for teaching communication, social skills, academic/cognition skills, and play.
The Association for Science in Autism Treatment considers video modeling to be "a well-established teaching method" for students with autism spectrum disorders.
Video Modelling and Behaviour Analysis: A Guide for Teaching Social Skills to Children with Autism