Lightnote - a website that shows a visual demonstration of sound waves and other scientific explanations to how music works.
Key Signature Games - This is a fun website that will ask you questions about general music knowledge and allow you to play classic video games when you answer the questions correctly.
The Wide World of Music - A website where you can hear an example of 100 different instrument sounds!
Apps for Smartphones/Tablets
Music Memos App - allows you to record and replay/share your recordings in an intuitive app.
Music Theory App - allows you to practice music theory on the go!
Tonal Energy App - a great tuner app that lets you know when your in tune with a smiley face!