I 've been there in october 2006 . (Beijing, Xian, Guillin, Hangzhou and Shanghai) and found a mix of some US and many European plugs. Always 220 V ! Maybe Hongkong has British plugs (not been there) . It's probably wise to buy a world 'plug'. Please note that calling from China to America or Europe is also expensive with a Chinese SIMcard! Caling from China to Europe with an European SIMcard costs about 1€ / minute. So I did'nt bother buying a Chinese card. Called 12 minutes a week. Wifi is everywhere in citycenters and cheap or free. Boingo has >10000 hotspot in China. (7.95$ /month.) GSM is everywhere, also on the countryside . You will be able to call fom the Great wall. It is generally not appreciated if you call to the Americas in the afternoon (China time) . A majority of the young Chinese speaks English. However be aware of young female students on Nanying Road in Shanghai asking if you want to practice their English.