Websites where you can search online educational resources and online lesson plans:

The Educator's Reference Desk has over 2000 lesson plans, 3000 links to online educaiton information.

TeacherXpress (British)

Education Network Australia (edna) is Australia’s leading online resource collection and collaborative network for the education and training community.

Its associated Oz Projects site has some good resources.

The Learning Federation is another Australian web resource.

Edutopia

Lesson Planet

PBS Teachers

Teacher's Pet - a free macro that sits in Word, allows you to easily create puzzles and many other activities.

TES Resource Bank - share materials with other teachers, recommend your favourite teaching resources, and rate and review other teachers' contributions and recommendations. You can upload and download files, or simply point people to web pages you've found useful.

The Lesson Plans Page (US) - over 3,000 free lesson plans.

HotChalk.com - sign up for free online teacher tools.