The following Education Databases include lesson plans for teachers. Try searching for "lesson plan" as a document type. Keywords to try include: art across the curriculum, arts integration, art lesson plans, etc.
Education Source: Education Source provides scholarly research and information covering all levels of education — from early childhood to higher education — as well as all educational specialties such as multilingual education, health education and testing.
Education in Video: Education in Video provides online videos developed specifically for training and developing teachers. Content includes demonstrations, lectures, documentaries, and primary-source footage of students and teachers in actual classrooms. The collection also contains a wealth of ready-to-use teaching tools, including course, study, and discussion guides, assessment checklists, and themed playlists.