Here are three rather useful links concerning the rights of photographers and the law.
If you would like to know the current law regarding image taking in the UK, USA and Australia then a series of PDF downloads has been made available with the details of the law and photography in those countries. They are not definitive guides to the law but they do give a good idea of your legal rights when taking images.
Click HERE for the UK version
Click HERE for the U.S version
Click HERE for the Australia version