The National Gallery of Art has terrific web resources for students and teachers of visual art. NGA Learning Resources offers learning packets, media, and online resources for teaching everything from 15th century European art to 21st century American art. Search by resource format, subject, or artist name. For instance, there is a teaching packet on Art Since 1950, a podcast of an interview with artist Jim Dine, and a slideshow of the Golden Age of Chinese Archaeology. Many of the resources are available as a pdf, podcast, or a webpage. Others you can request to borrow from the National Gallery of Art – just create an account! It’s free!