Making Music Fun is a friendly site with music games, music worksheets, free sheet music and music resources. These are geared toward beginner to early intermediate-level students.
There is a nice selection of note-naming worksheets as well as interval worksheets. They are visually appealing to young students. There are also composer word searches.
Making Music Fun is well laid out. Visit the Music Library and learn all about a composer. There are composer biographies, worksheets, lesson plans and sheet music. You can also access this information in the Print It section.
There is also an arcade, which contains two music theory games ("Music Distress" and "Eek Shark!"). All worksheets are available for free.