Help your students succeed.  Check out "The Education Trust":
http://www2.edtrust.org/edtrust

Free lesson plans, interactive and instructional materials for core classes.
www.thinkfinity.org

National Staff Development Council
http://www.nsdc.org

Free professional development training resources from Annenberg Media Workshops and Courses:
www.learner.org

Open-source teacher-generated curriculum materials for K-12 language arts:
www.curriki.org/