We have been using some fun yet educational websites to learn about different things recently!
Bones Game: http://www.sheppardsoftware.com/health/anatomy/skeleton/Skeleton_game_1.htm
Skeleton video: http://kidshealth.org/PageManager.jsp?lic=1&article_set=59294&cat_id=20607
Muscle video: http://kidshealth.org/PageManager.jsp?lic=1&article_set=59302&cat_id=20607
National Geographic for kids: http://kids.nationalgeographic.com