Easy to use and does what it says on the tin!
http://www.edexcel.com/i-am-a/student/Pages/Past_papers_app.aspx – Edexcel have just released and app on Apple devices that allows you and students to access all past papers. There is one for Google Play on its way. Now they have no excuse!
http://www.e.ggtimer.com/ – a really good classroom timer website.
http://quizlet.com/ – a site that allows you to both create online quizzes for your students and use others created by teachers all over the world.
http://ictmagic.visibli.com/share/cOmFVY – a clever way of defining learning outcomes.
http://ictmagic.visibli.com/share/OCvhyW – Spelling wizard, a way for students to learn topic specific spellings.
http://www.zondle.com/ – lots of games to play on lots of subjects and you can create your own.
Flash cards galore!