It is very important to start transition planning early (no later than age 13 or 14). If you and your child feel that he or she may attend a post-secondary education program, this is a good time to gather information about choices and appropriate preparation for specific programs. College may mean one type of high school program, getting ready for a job may mean another kind of curriculum is more appropriate. You will also want to begin looking for activities that focus on developing skills related to independence - either through school programs or programs offered by organizations specializing in helping individuals with cognitive challenges become autonomous, improve executive functioning and daily living skills, etc.
Agencies in localities throughout the country offer job-readiness programs, job training and placement. Enlist the services of your school district and local groups such as The Arc, the Learning Disabilities Association and other groups that work with individuals with disabilities. Your state's Developmental Disabilities Council can also be a source of information about opportunities to help your child get ready for the working world.