I was tipped off about United Mobile from an Andy Abramson post. Hadn't heard of them before, but it looks like they are very similar to MaxRoam, a service I had written about before.

United Mobile gives you a SIM with either a +44 (UK) number or a +423 (Liechtenstein) number, depending on which one you choose. The difference, which required some digging around on the site to figure out, is the mix of countries where inbound calls are free when you're in. Not sure why it's two different services.

Much like MaxRoam, when you make a call from a United Mobile SIM, your phone is hung up and then called back. When you answer, the system will connect you to your party. This arrangement ends up saving you a lot of money, when you're in the right country, anyway.

One wonders when the major mobile operators are going to start figuring out there's a market for reasonably-priced International roaming. Even so, this space will be interesting to watch.