Discovery Education aka United Streaming is a widely used source for videos on just about any topic you might need in your classroom. I really can't imagine teaching without such easy to use resources at my fingertips.
The Reading Lady is a great resource to all involved in literacy. It offers ideas for comprehension, author studies, poetry, writing, assessment (including rubrics), reader's theater (one of my favorite things, and even a blog. These are very user friendly ideas and lessons.
This site offers so much. The teacher activity packs allow teachers to upload lessons, links, and activities to their own websites. There is a PD section with online courses for teachers. Lesson ideas are connected to standards and are available for many different grades.
I love doing web quests with kids. They are fully engaged, problem solving, and practicing the skills they will use in their adult lives. This site sorts the quests based on grade level and subject area.