I found these free sites that look really interesting - www.biology4kids.com
Through that site you will find links to their other sites for chemistry, astronomy, physics, geography, math...
I havn't used them yet and they have a lot of info so haven't gone through it all but seems to have lots of info/facts. Pretty good for free.
more free sites
I use the internet quite a lot. In particular, Youtube selections make for something similar to TV, but not TV! You have to find them on your own, without your child, and save them for later (I find), as they take while to load and many are no good. But it has been worth the effort to find such things as Baharatanatyam dance, Bulgarian singers, Jingle dancers (Native American) - I can share the links if anyone is interested, as it takes a while to search through the many videos which are not appropriate and find some good ones!
Also, the British Museum has an excellent interactive website. You can play an easy-to-load "place the objects in the correct room" of an ancient Greek house, etc.
Also, Wikipedia has a section they are building which is for children. "Wikijunior". Might be of interest . . .
Elise