You're right to be curious about the evolution of cellular phone (mobile phone, whatever you want to call it) technologies and services here in the United States. In a word, we're far behind most of the rest of the world in terms of how we can utilize cellphones! Even in Africa they're pushing the envelope with innovations, including the Kenyan M-PESA service (as reported by the Christian Science Monitor).

Technology advisory service KPMG has also recently released a report talking about the future of money transfer via cellphone, and you can learn about it through IT wire.com, among other places online. The most important section:

"Unlike Europe where early mobile payment trials have failed to take off because of public apathy and lack of trust from banks, Asia Pacific may offer more potential due to the size of population and the high levels of mobile penetration."

Here in the United States, the biggest player I'm aware of in this space is Paypal, which lets you register your mobile cellphone number to an existing Paypal account then send simple SMS text messages to their service to transfer money from your Paypal account to either a specific phone number or email address. Gina Trapani has a splendid explanation of how to use this service at Lifehacker, but I'll simply note that a simple message like send 20 to 3035551212 or send 15 to user@hostname.com sure makes sending a Paypal payment quite simple. Unfortunately, though, many people are wary of Paypal and won't use the service.

Luckily, there are two alternatives, one of which I've written about before here at AskDaveTaylor, actually. The new one I didn't know until when I was researching this article is Obopay, which definitely looks cool. Learn more from CNet's Review if you're interested.

The other service, the one I've written about in the past and have used sporadically since? TextPayMe. As I wrote almost two years ago: "Simple, effective, and if your circle of friends are all hooked up, it's an easy way to transfer a few dollars around to pay for pizza, movie tickets or push a few bucks at a pal when your wallet's depressingly empty."

In terms of where all of this is going? Well, we now have wireless credit cards that work by you waving them near the sensor, so it seems reasonable to imagine that this can be coupled with a cellphone that has some biometric identity verification system (fingerprint? handprint heat pattern? retina?) so that by simply holding the phone near a sensor you'll be able to use it as a payment device, and that by putting two phones next to each other and setting things up properly, you'll be able to "tap to transfer" money from one to another.