Oh, and just for the record, my phone mustn't have been properly unlocked the first time - as after following the restart steps again, it now accepted a US SIM with no problems (so must now be properly factory unlocked).

FYI, there are actually several other options for travellers to the USA. In addtion to Simple Mobile, there is also h20, Red Pocket Mobile and another. All around the $60 per month with unlimited calls, text and different levels of data. Some with full 3G speeds (unlike the 2G speed of the Simpl...

Oh, and there is also now a $40 per month plan, with: Unlimited Phone Calls (Local & Long Distance) Unlimited Texting (Domestic & Global) Unlimited Internet at up to 3G speeds* International Long Distance Options Etc  https://www.mysimplemobile.com/plans-40-unlimited.aspx

Awesome. So great to hear about this. However, I'm in San Fran now, with an unlocked iPhone 4S (Vodafone) - and unfortunately it is not recognising the SIMPLE Mobile (or any other US SIMs). Vodafone (Indian customer service representative) has assured me that my phone is unlocked (I have follo...