Can anyone recommend a UK-compatible (GSM) mobile phone provider that does business in the United States -- preferably one with retail locations? I will be moving from the US to the UK this summer and would like to have a compatible phone on arrival. My present cellphone -- I know, I know, I need to get used to calling it my "mobile" :-) -- is old and weary and I am due for both a new phone and a new plan. Many thanks for all the help this site has already provided!