For a starter addressing common misconceptions try the excellent Classic Mistakes resources by Nigel Hopley.
A superb resource to use in class (or for students to use at home) to address misconceptions is Craig Barton’s and Simon Woodhead’s Diagnostic Questions site. The site has over 1700 questions with carefully designed multiple choice responses to address common misconceptions. For further details see these posts.
From Count On comes a very clear series of documents on common misconceptions. For each topic an explanation of how the misconception arises is given, together with some exercises aimed at reinforcing the correction needed.
One of the new year resolutions I suggested was to reread Malcolm Swan’s excellent ‘Improving Learning in Mathematics‘, this includes a section (5.3) on exposing errors and misconceptions. An activity suggested there is to let your students become examiners and mark the work of others, this works very well, I have highlighted some excellent resources for this on the ‘Spot the mistake!‘ page.
Many of the outstanding resources from the Standards Unit address common misconceptions; see PD2, learning from mistakes and misconceptions. See also the resource hosted by STEM Learning – you will need to create a (free) account to view the STEM Learning resources.
Examination boards often publish helpful material which addresses common misconceptions, such resources can promote very useful class discussion as can examiners’ reports. From AQA for example, have a look at the Feedback documents on each unit available here (scroll down the page and look in the section on Teaching Resources) and another resource here.
Great questions can be used to expose misconceptions, diagnostic questions have already been mentioned above; for further sources of questions see Rich Questions.