Musical tutorial site
Recently, while searching for a specific piece of sheet music, I stumbled across a site full of music tutorials and other resources. "Making Music Fun" is primarily aimed at elementary school children, but would be useful for anyone trying to learn to play an instrument, read sheet music, or learn other musical topics.
They have posted a series of videos on YouTube teaching how to play songs on various instruments (just search for makingmusicfun). The site has sheet music for several classical pieces as well as childrens’ songs and is divided into sections based on instrument. Even better, there are mp3s on the site so you can hear the piece before you commit to learning it. Making Music Fun even includes a brief biography about the composer of each piece.
If you are a music teacher, have children, or are an adult trying to learn the basics of music, I would highly recommend checking out this site.