Here are two web sites that are convenient to use and educationally sound.

1. KidZone ( KidZone’s printable preschool and kindergarten worksheets help younger kids learn their letters, numbers, shapes, colors and other basic skills. 

KidZone’s printable grade school stories and worksheets help older children learn phonics, reading, creative writing, math, geometry, science and geography.

2. Edutopia ( Browse this big list of education topics to find strategies, programs, and resources. This site is an invaluable resource for public and home school educators.