OBVIOUSLY THE BOFFINS at Truphone have nothing better to do than play with their calculators at the mo because they've worked out how long it would take to save £99 on calls while 'roaming'.

The answer is apparently one hour and 54 minutes. This assumes you're a Brit and you've purchased the 8GB version of the phone for £99 and are now stuck on the standard 18 month contract with O2.

The other assumption is that you download (for free) the Iphone compatible version of Truphone from Apple's official Itunes App store.

All you'd then need to do is be daft enough to make a regular cellular call to a UK landline number for 114 minutes from the USA instead of using Truphone plus a [free] Wi-Fi link and you'll save that £99.

Alternatively, make a roaming cellular call while you're with the EU back to a UK landline and it will take you a mere 300 minutes to save your £99.

Truphone made its calculations using O2's published tariffs which are available online here. It's obviously must-do reading for Iphone owners.

Truphone's version of how much calls will cost if you use a free Wi-fi connexion are laid out here.

The INQ suspects, however, that this must just possibly be a publicity stunt to point out how popular the Truphone app is with existing Iphone 3G owners. Truphone reckons it must be at least within the Top Ten favourite apps and cites this blog here.

Of course ,you can save yourself £99 by not buying an Iphone at all and installing a much better browser (like Opera's) on your 3G Nokia but that wouldn't be so much fun would it? µ