The Plagiarism Advice Agency in the UK is at http://www.plagiarismadvice.org/ They provide advice, training and resources for those in the education sector, schools as well as further and higher education. The focus has been more on higher education, but apparently they will also be publishing guides for those in secondary schools (I couldn't see them there yet).
The 4th International Plagiarism Conference will be held at Northumbria University, 21-23 June 2010, papers to be submitted by 29 January 2010. http://www.plagiarismadvice.org/conference.html
Another useful site is Plagiarism today, http://www.plagiarismtoday.com/ , which is run by Jonathan Bailey (based in the USA) who says "am not a lawyer. I am just a legally-minded Webmaster/Writer frustrated with the plague of plagiarism online and doing something about it." However, he posts interesting commentary and news, though obviously with a US perspective on the legal situation.
Photo by Sheila Webber: metro, Milan, Italy, August 2009