The following are teacher/Principal approved websites, suitable for Junior High students:

American Journey 8
American West - Pony Express Information
A Plus Math
Belle Plaine Public Schools! 7/8
Classzone
Compass Learning 7/8
Cool Math
Dictionary 7/8
Discovery Kids
First in Math 7/8
Funbrain
I Know That
Math Playground
McGraw Hill Glencoe 7/8
National Geographic for Kids 7/8
National Geographic 7/8
Northwest Evaluation Association
PBS 7/8
Read Write Think Comics
Read Write Think
Scholastic Kids
School House
Study Island
The White House 7/8
Time for Kids 7/8
Zingy Learning 7/8