Edweb blogger, Sara Ellenz, has created several resources for teachers looking for good technology tools. Once you go to one of her pages, you may find yourself poking around her other pages.
One such tool is her Instructional Websites page. On this page you'll find a list of websites that can be used in all content areas. Not all of the websites were created for educational purposes in mind, like Google docs, yet they can be used very effectively to help students communicate, collaborate, think critical, and use their creativity. (The 4C's as defined by The Partnership for 21st Century Skills.) In addition to describing the purpose of using each tool in an educational setting, Sara provides short descriptions of how teachers and students will benefit from using each tool. It's really worth your time to browse this page if you are interested in using technology more effectively in your classroom.