The Ages and Stages Questionnaire is a developmental screening tool that can be used by psychologists, pediatricians and others who care for children. It is used to identify potential developmental delays and signs of autistic spectrum disorders.
Healthychildren.com is a website for parents, powered by pediatricians. It has information about typical development of children. If you suspect your child may have a developmental delay, you should talk to your pediatrician, family physician or health care provider to discuss developmental screening.
Here is a link describing typical developmental milestones by age:
http://www.healthychildren.org/english/ages-stages/Pages/default.aspx