A fantastic collection of tutorials on all areas of physics. Students can see the connections of the topics through the layout of the site. There is also a math page that most AP Physics students find very helpful especially in the AP Physics C level class.
What a great site for kid friendly explanations on some really complex material. There are sections for interaction while the student goes through the tutorial to help in their understanding.
What a great way to help students understand current events in particle physics! The particle adventure walks student through the standard model. It includes short "quiz" questions along the way to make sure that students are truly understanding the material.