Besides the many free worksheets available, this site offers nine online worksheet makers and 16 graphic organizer generators. They include Crossword Puzzle Maker, Word Search Maker, and a Venn Diagram.
http://worksheets.teach-nology.com/

On the Web since 1996, this site targets preK-3 children using a pictorial interface that invites them to explore the Internet as a source of information. More than 600 activities, both on- and offline, are accessible through the site.
http://www.enchantedlearning.com/Home.html

In the spring of 1996, the founders of Education World recognized the need for a Web site that would make the Internet easier for educators to use. They wanted to create a home for educators on the Internet, a place where teachers could gather and share ideas. They wanted to create a complete online resource where educators could start each day to find the lesson plans and research materials they were looking for.
http://www.education-world.com/