The American psychological association is a site where student can read about a lot of topics, in a very high academic level. For some students this can be quite interesting and a good challenge, but the site contains more easy reading too, and also a lot of links and very good topics, and some huge databases.
This site is for searching further information. It contains a lot of links to theories, articles, experiments, history, and also lots of recourses for further reading. This one can be quite helpful for student assignments.
This is an easy site, with a lot of short and well-explained info. Here you can find "something about everything", and can be a good place to start when you should introduce a new topic in class, or as a starting-point for students.
This site is also on Facebook, so you can get updates almost every day.