Tech Ease is a great resource for teachers and students to learn about computers and basic tech support. It is is broken down into Mac, Windows, and accessibility uses.
Under each, there are subtopics such as using computers in the classroom, images, file sharing, chat, videos, email, hardware, the internet, and much more. There are ideas on using technology for accessibility with disabled students also.
Tech Ease is easy to navigate and has a huge amount of information available for educators. This is site you should definitely share with your colleagues and students.