Several trips ago I picked up a 2G Orange PAYG SIM and set it up on their Call Abroad Tariff. This setup ran me 5p per minute to call the US, and of course incoming calls were no charge.

Before my last trip I ordered a pair of Orange 3G SIMs via Ebay for my wife and I so we would be ready when we arrived. We are both data addicted so that was a big factor.

I pointed a pair of US VoIP numbers to the Orange UK SIMs and as we boarded our flights we forwarded our cell phones to the US VoIP number to achieve "seamless" roaming at 26 cents per minute instead of 99.

Once in the UK we set up Orange's 5 quid per week for "unlimited" data plan on each of our SIMs. So for 10 days there unlimited data on Orange's 3G network for the both of us was a total of $40. We also talked frequently back to the US at 5p/minute.

For my money Orange's Call Abroad with 5 GBP/week "unlimited" data on their 3G network is the best deal going, especially when combined with a forwarded setup from the US. Incoming calls at $0.26/min and outgoing to the US at $0.10/min is on par with a US pre-paid plan but instead I'm in the UK!