One of the most compelling aspects of the O2's unlimited data iPhone tariffs is the ability to get free access to The Cloud's wireless hotspot network.

The Cloud has 7,500 hotspots across the UK including most of those at train stations and in a surprising number of pubs - there's one inside every one of those Itbox gaming machines you might have played Who Wants to be a Millionaire? Or Deal or No Deal? On.

Sparse EDGE coverage in the UK

O2 is playing up the iPhone's Wi-Fi capability ahead of the iPhone's launch today, when there will only be 30 per cent EDGE coverage - there is, of course, no 3G access in the iPhone.

"Our deal with The Cloud means that Apple iPhone users - who are likely to have Wi-Fi connectivity at home and at work already - will have access to free Wi-Fi at 7,500 hotspots across the country," an O2 spokesman told Tech.co.uk.

Unlimited access across The Cloud's network normally costs upwards of £6.99 per month, or £3.99 if you have an iPod touch.

Finding hotspots is easy. Simply type in your postcode or current location at The Cloud's Hotspot Finder and you'll get a list of the nearest places to go for access, what type of outlet it is and how far it is from your current location if you've specified one.

Clever connections

What's really clever is how the hotspot functionality is built into the iPhone. "The first time you turn up at one of our hotspots, you select the network, open the browser," explains Owen Geddes, Group Director of Business Development at The Cloud.

"As soon as you open the web browser, you'll see a page that asks you to input your O2 phone number. And as long as your phone number is tied to a valid iPhone tariff, then it immediately authenticates you onto the network from that point onwards. So it's really, really simple."

Ah yes... but what if you walk out of one hotspot and walk into another later that day? Easy; The Cloud's network recognises your phone whenever you walk into another hotspot.

It's clever stuff, though you can't access other networks that partner with The Cloud such as BT Openzone, or hotspots abroad. You also won't be able to access Starbucks' access points unless you pay for it - they all use T-Mobile's hotspot network. That last point is a little strange, since Apple has launched the iTunes Wi-Fi Music Store in conjunction with US branches of the coffee chain.

As for the iPhone itself, Geddes is clearly a convert. "Am I getting one? Absolutely, I've got one. They're great devices. Boy they're hard to get hold of, I've been using it for around 10 days."