A great site with activities, quizzes, videos and even karaoke about every area of the science curriculum. Very useful when introducing new topics.
http://ictmagic.wikispaces.com/Science
This is a resource-rich site, with a math, language and comprehensive science content. Slideshows, videos and comprehension quizzes have made this a site I will use often.
A superb collection of maths study guides, quizzes, games and activities for every area of the maths curriculum. A must for any maths teacher.
http://ictmagic.wikispaces.com/Maths