Sqworl is an easy to use site and once you register you can create a sqworl about anything. You can also search sqworls other people have created. Here's a link to the sqworl I created tonight focused on interactive multiplication sites for my third graders:
Here's a link to sqworl's homepage:
I am so happy about this! I have experimented with several ways to share websites with my kids. I think I may have discovered the best answer yet!