Actually, orange call abroad recently reaised its rate to call the USA to 7p/minute and I think it is rounded up to the next highest minute. Still a very good rate but...
Right now, I think the best bet for calling from the UK to the USA is T Mobile UK....you can couple that with an outfit called yourcallworld (
www.yourcallworld.com) and calls to the USA and most other foreign destinations (landlines only but of course to the USA and canada it doesn't matter) is 3p/minute...the site explains how you can get a T Mobile UK sim card for next to nothing (provided you have a UK mailing address) or I have found an offer on ebay for less than $10 shipping included to the USA.
You can also purchase a bundle on T Mobile UK for £2 which will allow 50 minutes of calling to the USA which will not go through calling an auxillliary number as is the case with yourcallworld.....by my math that comes to 4p/minute although it has limited validity (60 days).
Both Orange and T Mobile UK do subcribe to eu euro tariffs for use in roaming in Europe outside the UK...I think it is 34p/minute to make a call a 19p/minute to receive a call within the eu.
And unlike the French thieves, it is very easy to keep the cards active. If set up for data, every 3 months just download a free ringtone or something like that or send, a bit more expensive, a text message from the USA which counts as an activity and keeps the sim card active.