http://teacher.scholastic.com/lessonplans/

-Lessons grouped by subject and grade level

http://www.lessonplanz.com/Grades_K-2/

-K-2 lesson plans by subject

http://teachers.santee.k12.ca.us/carl/

http://www.theteachersguide.com/

-Lesson plans by subject

http://www.ilovethatteachingidea.com/index.htm

http://www.teachnet.com/lesson/index.html

-Sorted by subject

http://www.aolatschool.com/primary/index.adp

-Lessons by subject

http://www.eduplace.com/

-Lessons by grade and subject

http://www.fcps.k12.va.us/KingsParkES/staff/index.htm

-Technology lessons by grade level

http://www.bridge-rayn.org/lessons.html

-Lessons by theme

http://www.teachingideas.co.uk/

-Teaching ideas

http://www.teach-nology.com/

-Lessons, activities, rubrics, etc

http://www.edhelper.com/

-Activities and lesson plans 

http://k6educators.about.com/cs/k3lessonplan/index.htm

-Lesson plans, most are for free

http://school.discovery.com/lessonplans/

-Lessons by subject and grade

http://teachercreated.com/lessons/

-Lessons from Teacher Created Materials

http://www.amphi.com/~tlcf/lessonplansK-39900.htm

-Lesson plans for K-3 teachers

http://atozteacherstuff.com/Themes/

-Thematic units by subject and grade

http://hometown.aol.com/iteach345/page2/index.htm

http://members.aol.com/DonnAnCiv/1Literature.html#H

-K-12 literature lesson plans

http://members.aol.com/sskufca/bookunits.htm

http://illuminations.nctm.org/

-Math lessons grades K-12

http://www.randomhouse.com/teachers/guides/grade/

-Teacher Guides and lesson plans by grade level

http://www.sdcoe.k12.ca.us/score/cyberguide.html

-CyberGuides are supplementary, standards-based, web-delivered units of instruction centered on core works of literature.

http://www.csun.edu/~hcedu013/

-Lesson Plans and Resources for Social Studies Teachers

http://chem.lapeer.org

http://www.thegreenfrognews.com/Science.html

-Science lessons

http://highschoolace.com/ace/english.cfm

-Language Arts lessons