Some of my current favorites...

Thinkfinity: Use Resource Type filter to sort for Interactives

ReadWriteThink: Student Materials

NCTM Illuminations: Activities

Science NetLinks: Tools

Smithsonian's History Explorer: sort for Interactives/Media

BBC Schools - Ages 4-11

BBC Schools - Bitesize

KS1 Bitesize - Primary

KS2 Bitesize - Intermediate

Show Me: Games and Fun

PBS Kids - Primary Grades

PBS Kids Go! - Intermediate Grades

Teachers' Domain

PBS Teachers | Resources for the Classroom

TVO Kids

4Kids

Arcademic Skill Builders

MATRIX Learning Games

But wait... There's more!

NGA Kids: The Art Zone

Kinetic City

National Library of Virtual Manipulatives | eNLVM

Thinkport: Virtual Arcade

Scholastic Computer Lab Favorites

Edheads

Poptropica

Manchester GATE School: Student Resources

Find More: Use any of the Search Engines... Google | Yahoo | Ask

hint: enter your curriculum topic and and add the keyword "interactive

http://www.cotwcourses.net/cvcue/interactives/