Try these sites for great online music learning options:

Classics for Kids - Fun interactive music education games for kids

Joytunes - Bringing music learning into every single household around the world, whether it’s piano, guitar, sax, singing, or any other instrument

MusicTheory.net - Lessons, tools, exercises and more

Yousician - Yousician offers thousands of songs, exercises, and teacher-crafted lessons all in one app

Noteflight - Create, teach, share, sell and purchase music

Guitar Pro - Access to thousands of tabs

Jazz Tutorial - Learn Jazz Piano online with step by step video tutorials

Musescore - Create, play and print sheet music