(Sample link) White House for Kids http://www.whitehouse.gov/kids/whlife/index.html
(Sample link) National Geographic for Kids http://www.nationalgeographic.com/kids/
Reading activities to learn ABC's, sounds and words with games http://www.starfall.com/
Click the books for Language Arts for practice with letters and sounds. Click the numbers for practice counting and learning numbers. http://www.internet4classrooms.com/month2month.htm
Cool Math Under Cool Math Highlights click on math4kids then on math kids. Enjoy http://www.coolmath.com/
ABCYA Click on Kindergarten. Enjoy http://www.abcya.com/
Different activities for kids http://www.funbrain.com/index.html
Learning games for children http://www.primarygames.com/
Phonics fun for early readers http://www.teacher.scholastic.com/clifford1/index.htm