Teachers' Domain is a great free science resource from PBS I found. It has a wealth of animations and lesson plans. You can create folders and put both Teachers' Domain and internet links in them. You need to register, and you need to have an organization, though you can enter your homeschool organization (they ask for name, address, and telephone.) The site has a built in "trial" where you can view 8 resources without registering.
Each animation can be viewed at the site or even downloaded, and comes with discussion questions. They are linked to state standards (if you like to look at those things) and to a variety of lesson plans. Most of the animations I've viewed so far have both audio and visual components, and some are interactive.