http://www.enchantedlearning.com/music/
This website is great for for both teachers and students. Enchanted Learning provide almost everything you want to know about music. They have a list of Musical Instruments, Music Theory Printouts, Music Sheets, Composers and even a Music Calendar. This website is good for Pre K through 12.
http://www.musictechteacher.com/music_quizzes/music_quizzes.htm
Music Tech Teacher provides broader knowledgable tools for children who already know how to play a musical instruments and wanted to polish their skills even more. They also provide quizzes about all types of musical topics, such as: Music Notes, Rhythm, Theory, Famous Composers, Chords, Key Notes and lots of fun learning experience available in just one click!
http://www.kidsmusicround.com/
This website is so fun exciteing especially for ages 2-4 years old. As soon as you click on the website, music will be playing entertaining you and your child! There are variety of music selections for young children to sing a long and even improve their social/emotional skills and motort skills as well, like clapping, bouncing, dancing and other fine motor movements.
http://www.storytimesongs.com/index.html
Story Time Song is a great website for preschoolers. They provide beautiful story time songs, children's song ( with guitar chords), Homemade Musical Instruments ideas, Music Learning Activities, Games, and Fairy Tale Songs. It is very well written and easy to understand their instruction/ explanations regarding the activities you wishes to do with your child or students.
http://www.classicsforkids.com/music/orchestra.asp
Classic For Kids is a good website which shows children different kinds of intruments and what family they belong. This is also good for children that came from a different country/cultures so they can learn and share which instruments are originally comes from. As soon as you click this site, you will an interactive Orchestra setting which is very cool! It shows young children the actual place where all the instruments are set up in real life's musical concerts. Added to that, they also provide a link to help grown ups to scaffold their child into learning, encouraging and inspiring them into music.