Artsconnected - This site from The Minneapolis Institute of the Arts contains teacher resources, library & archive resources, and online activities.   

Artchive - This is a comprehensive collection of work and biographical info about both contemporary and historical artists.                                                                             

ArtsEdge - This is an arts education site from the Kennedy Center containing lessons, activities, links and professional resources.

Getty ArtsEdNet - An excellent art education web site from the Getty Museum featuring lesson plans, curriculum ideas, virtual gallery tours and an electronic discussion list for art educators.

Art History Resources on the Web - A huge meta-list of links to historical artwork organized within various periods.

CalPhotos - Access to over 34,000 images of plants, people, animals and landscapes from the Digital Library Project at UC Berkeley.