It baffles me why phone chagers dont come with a switch bulit in automatically. Heres a device which mayt help reduce them lovely bills if you have a new sony or nokia phone. Do remeber not all phones of the same maker have the same connector.
httphttp://www.expansys.com/p.aspx?i=169413://
sony
http://www.expansys.com/p.aspx?i=169413
nokia