Have you tried Biology4Kids or any of their other related websites (Chem4Kids, etc.)?

http://www.biology4kids.com/
That one has links to all of their other sites.

In terms of science kits, Ward's Natural Science has some neat forensics kits (my kids have liked DNA kits), and dissecting owl pellets is also a fun activity. There are a lot of places online that sell those. You get to pull out the bones and reconstruct the animal that the owl ate to find out what it was.

Study Strategies for Accelerated Learners