If you have an iPhone and you also happen to have Google Voice (as I do), I advise you to do the following:

Access Safari from the iPhone and go to http://www.google.com/mobile/voice/. Alternatively you can click on this link and go to that page and hit a button which will send a link to your iPhone. Either way you now have a URL that will allow you to use Google Voice from the iPhone. The iPhone will let you convert that to an app button and when you touch that button the Google Voice app runs – just as if it were an iPhone app.

Why would you want one?

Because using it:

• SMS is free
• US calls are free
• International calls are cheap
• IT ALL WORKS ON YOUR iPhone

It means you don’t need a usurious voice line rental deal with AT&T or anyone else in order to make phone calls from your iPhone. You will still have to have a usurious data deal with AT&T or someone else in order to make the calls, but that’s less expensive. Indeed you could simply buy a MiFi (a portable WiFi link) and use that. You don’t even need an iPhone, you just need an iPod Touch.

What is it like using Google Voice from your iPhone?

It is identical to using your iPhone. There is one small difference. Google Voice is working from a separate contacts database – the Google Voice one. It is a fairly trivial task to keep your Google Voice and iPhone contact list in step, so no need to worry about that.

Why am I writing about this?

It is a fact that Apple banned Google Voice from the iPhone, probably under pressure from AT&T – or maybe because there was something in its contract with AT&T which ensured that Apple wouldn’t knowingly let such applications run. Those who enjoy schadenfreude may take delight in the flouting of Apple/AT&T’s wishes in the appearance of Google Voice on the iPhone, but actually the story here is much bigger than that:

Google just demonstrated that you don’t need to develop an iPhone app to run an app on the iPhone.

You can run the whole application in your web site. You can charge for it direct and you don’t need a jail-broken iPhone to run it. You don’t have to push your application through the slow app approval process and if Apple doesn’t like you app, it doesn’t matter.

Clearly, this does not mean that it’s over for the iPhone App Store. There are device specific apps which will always need to come through the app store. Also there’s a neat symbiotic relationship developing between iPhone developers and Apple, where Apple helps promote the better iPhone apps and everyone makes money. But Apple’s control over what runs and what doesn’t, is over.

And as for the carriers.

It is patently absurd for the carriers to charge so much for voice calls and SMS messages, and mug you outrageously for any call that you make if you dare to go abroad. Google has an alternative proposition. Calls cost nothing in the US to US phones. SMS messages cost nothing. International calls are cheap. Outside the US you get cheap call rates no matter who you call.

I like this proposition.

In fact, I’m sold on it.

If you aren’t signed up for Google Voice, I advise you to do so. It was a great service without this little nuance.