This is the site for the California Department of Education. The main reason I go to this site is to pull up the curriculum standards by grade level. This site also offers other resources and information that are important to classroom instruction and education policy. The best part of all is that you create the worksheet and its ready to print immediately. You don't have to worry about downloading the worksheets to another file, etc.
Worksheets are for elementary and secondary education.
Anywhere from lesson plans to clip art to education news, parent news, and teacher news. I love it for the fact that I can find all sorts of lesson plans here. I just recently found this site and found it to be an incredible resource tool. You can find advice for new teachers, classroom management strategies, educational clip art, and other very useful tools. As I learn more about importing images, etc.