1. Google - http://www.google.com/educators/tools.html - Google has internet search, educational search, free blog hosting, Google Docs, free web site hosting, and more. There is a huge amount of tools and resources available from Google for free for educators. There is also email, calendar, and task lists that are all free. These applications can help teachers and students.
2. Evernote - http://www.evernote.com/ - Evernote has a free account and is a great resource to take notes, clip information from the internet, and stay organized. Keep your lesson plans and other notes on here and have access to them from anywhere.
3. Tech & Learning Magazine - http://www.techlearning.com/ - this magazine has a huge amount of resources, links, and articles about technology and education. There are news articles, how-to articles, blogs from ed tech leaders, and reviews of educational technology, along with other links and resources. It is free to subscribe and you can get either print or electronic copies.
What are your favorite/most useful resources?