A very popular book among homeschoolers, Discovering Great Artists, Hands On Art for Children. The following excerpt has been taken from the books website.
Children ages 4-12 experience and enjoy painting, sculpting, drawing, and building works of art in the styles of the great masters such as Van Gogh, Michelangelo, and Rembrandt. 150 art ideas divided into five main chapters introduce children to over 80 great masters from the Renaissance to the present. Chapters include: Long Long Ago (Renaissance and Post Renaissance), Sunny and Free (Impressionists and Post Impressionists), Wild and Wacky (Abstract and Surrealists), Art Today Everyway (Pop, Op, and Modern), Make It and Play It (Games and Activities Kids Can Make), and a detailed Resource Guide (Indexes, lists of artists' birthdays, and many more things kids will love).
The website also has an online supplement for the book which you can see here and an online teaching supplement. Also check out this part of the site for some great art activities as well.