Arts Education Curriculum Guides - from Saskatchewan Education. Quite detailed units and lessons are provided but you will have to establish the correlation to the Ontario curricular expectations.
Kennedy Centers ArtsEdge - "Linking the Arts and Education Through Technology." Information and curriculum resources for teachers.
KinderArt - free Art lessons for K-12
The Incredible Art Department - a rich resource for teachers
Elmers - This site includes a "Kidz Zone" and Teachers' Lounge for arts and craft ideas and lessons.
The On-Line Visual Literacy Project This may not be an appropriate resource for students but it could provide valuable background for teachers of visual arts.
Building Visual Arts Lessons - from the Getty Museum
Crayola Art Education Even though this is a "commercial" site, the lesson plans offered are very good.
Creative Drama and Theatre Education Resource Site
Creative Drama Lesson Plans - lesson plans developed for use in a Creative Drama Classroom (and a few games and lessons from others as well) "All of these lessons have been tested and proven successful in the classroom."
Reader's Theater Editions are scripts adapted from stories by Aaron Shepard and others -- mostly humor, fantasy, and world tales from a variety of cultures. A full range of reading levels is included, with most scripts aimed between grades 3 and 9.
Songs 4 Teachers - resources and free samples organized by theme.