We are doing music appreciation afterschooling with Themes to Remember and supplementing with books/cds from the library for each composer. I am trying to loosely follow the 6 year schedule from the Themes to Remember website, and so far, my kids love it! (kinder and first grade) They are learning the vocabulary (a lot of which they knew from "Little Einsteins, anyway) and they love the songs and lyrics. They will both start piano next year, as well.
They are both in ballet, so I kind of consider that to be part music/part art appreciation.
For other art, we read various children's books about artists, such as Degas and the Little Dancer, Katie and the Mona Lisa, etc. I thinking about using Usborne Art Treasury next summer, or their Introduction to Art. They also enjoy drawing books.
We are Buddhist, so we also read children's stories like I Once Was a Monkey, etc.
We try to incorporate a lot these extra topics into reading material, so it doesn't seem overwhelming.
HTH.