http://atozteacherstuff.com This site will help teachers build a thematic unit. These themes feature quality links to thematic units and lesson plans, resource pages, book activities, books, and professional resources organized by theme.
http://emints.more.net/ethemes eThemes is an extensive database of content-rich, age-appropriate resources organized around specific themes.
http://school.discovery.com/schrockguide This is a great website for lesson plans and teacher tools.
http://teacher.scholastic.com Scholastic site - Has teacher resources and lesson plans.
http://www.lessonplanspage.com Thousands of lesson plans in all main subjects.
http://www.aloha.net/~bry/teaching/ This site is an informative listing of websites where a teacher can find help formulating language arts lesson plans. A language arts resource website listing is also available.
http://www.askeric.org - AskEric. Everyone should know this site by now.
http://www.col-ed.org/cur/ CEC Lesson Plans - This website is produced by the Columbia Education Center at Columbia University in New York. It is developed in conjuction with Microsoft to list some of their lesson plans on the new Encarta Lesson Collection, which you can access directly from this website. Lesson Plans couldn't be more simple, first organized by subject, grade levels (K-5,6-8,9-12), then are simply listed and you pick your area of study. All of these are in printable version.
http://www.educationworld.com This site is as it claims - the educator's best friend - with detailed information on stories, poetry, language, reading and writing for grades K-8. You will also find an archive section full of teacher lessons, current school issues, and tech in the classroom.
http://www.enchantedlearning.com This site is booming with hundreds of activities and reproducibles on every subject and area imaginable from preschool to high school.
http://school.aol.com This very comprehensive site is excellent for both teachers and students with its content areas ranging from subjects and standards, lesson plans, special needs and counseling, professional development, classroom tools and tips, education news and research and reference materials.
http://www.riverdeep.net These language arts products help build students' communication skills while teaching principles using real-life situations.
http://www.schoolhousetech.com This website has great software for sale to help teachers create their own worksheets.
http://www.teach-nology.com Great site for making your own word searches, crossword puzzles, or rubrics. Also good for theme units, games, and lesson plans.
http://www.usmint.gov Website of the U.S. mint which contains information, and games revolving around coins/money. Could be useful for math.
http://bostonkids.org Website of the Boston Children's Museum. Has lots of resources for teachers.
http://www.yahooligans.com This is a great website for finding information that is presented at a child's level.