If you believe the rumours, Facebook is working with INQ mobile and AT&T on an iPhone-style phone, and a network to go with it.

It makes perfect sense - a Facebook phone has the potential to dissolve geographical boundaries and equip you with a globally-transparent currency that'll let you do things that you can't do in your local currency.

A phone and currency?

Let's take it from the currency. Facebook has one thing that everyone wants - users. So many, in fact, that it ranks the fourth largest country in the world. And every country needs currency, even a virtual one.

Facebook calls its virtual moolah "Credits". It debuted last year, and is now the only method of payment for the games created by Facebook's number one third-party developer, Zynga

How do you acquire these virtual Credits? Facebook sells them in gift stores in the US. Expect them to be available in a UK store near you soon.

So at the end of a virtual currency is a physical bank account with real cash. Inside Networks, which tracks Facebook apps, says the virtual currency is expected to generate $835 million in hard cash this year. From here on, it's only going to grow. Facebook projects that its virtual currency will be used to purchase much of what is sold on the site, and Facebook gets 30 percent of every sale.

The advantage of a virtual currency is that it's impervious to physical borders, and streamlines International transactions. If an item costs 5 credits in the US, it costs 5 credits here in the UK.

Happening now

Now take this virtual currency a step further, and you have access to a broad range of items which you could pay for with virtual Credits. And you'll do it using your Facebook phone.

Far fetched? No, it's already happening. There's the yet-to-be-launched Social TopUps service which allows Facebook users to directly recharge a mobile phone user's prepaid mobile phone in another country.

Of course something like SocialTopsUps requires the participation of network operators across the globe. To tie up with the operators, Facebook needs its own phone.

The rumoured phones are said to be modeled on the iPhone, but the similarities will extend far beyond aesthetics. Much like the iPhone, Facebook would want to meld its platform with the phone's hardware. If it's your own money involved, who would you trust as a user - a third-party app using the Facebook API or an official, tightly integrated Facebook phone and app?

The possibilities of a cross-border virtual global currency and the convenience of a phone, are limitless. SocialTopsUps and a Facebook-badged phone will whet your appetite. Soon you'll be able to use your Facebook phone and virtual credits to pay for items in the real world.