I live in the UK and have an iPad 2(3G) and an iPhone 3G. I will be visiting California for 3 weeks in September 2012, I will be using the iPad for blogging, social media and a little Internet access. The phone will be used mostly for messaging and the odd call back to the UK. Can anyone suggest a combined Sim card that will work in both devices (that I can swap between the two). I don't mind paying a bit extra for something that will work most places. Thanks!