Below is an extensive (hopefully) list of chemistry websites that I found extremely interesting and useful. This list will be updated frequently as the web is ever expanding. I would also appreciate any excellent chemistry links you would like to share with us.
Lots of good stuff on IB Chemistry website
flash demos, animations and ppt presentations - although specifically for IB it covers most of the topics required for A'level
Check chemistry lectures for pH, concentration and balancing&stoichiometry lectures and questions. Plus much more specialized site www.pH-meter.info if you need info on pH measurements.