Let children apply stamps or labels to envelopes or let older children sort mail by name or ZIP code. Remember to keep their tasks age-appropriate. If you give a 3-year-old a task he or she can't perform well, the child will get upset, you'll be frustrated, and you'll probably have to redo the task yourself, thereby wasting a lot of time and energy. Giving children tasks they can perform well allows them to feel important. They will have a sense of contributing to your business and you will be able to get some tedious chores off your plate.
Excerpted from Starting a Home-based Business