When Apple announced tethering plans for the new iPhone at yesterdays opening Worldwide Developers Conference (WWDC) keynote speech in San Francisco the news was generally greeted favourably.

The ability to share the 3G connection on your iPhone with your Mac notebook or PC laptop has long been on the wish list of many, the popularity of mobile broadband evident by the number of high-street deals currently available from the likes of Carphone Warehouse.

Scott Forstall, senior vice president of iPhone Software at Apple, confirmed tethering would be available initially depending on carrier availability, with the UK's O2 among the 22 carriers in 44 countries offering the service at launch.

It was a rare occasion when UK O2 customers beat US AT&T customers where the service will be offered, along with MMS, until later in the year.

O2 has revealed the cost of tethering, partnering with The Cloud 5,000 hotspots, and later BT Openzone, for the service. Penalties for exceeding your 'iPhone Internet Tethering Bolt Ons' bundle limits are also listed while the small print adds, "excessive usage policy applies to all unlimited services."

Here is an image that O2 has provided detailing tethering costs for Pay Monthly customers.

And details of O2 tethering costs for business customers.

Like O2's upgrade path for older iPhone owners, the price structure looks likely to be a cause for concern to many, especially those looking for the occasional tethering option when a pay-monthly mobile broadband offer might prove a much better deal.

One reader called Siobhán said said, "The prices are daft in a recession or otherwise, waiting six months to upgrade is a pain and the tethering costs are just plain mean. There's no flexibility for people like me who would want to use tethering only occasionally."

Broadband Genie currently lists the 'Top 10 most popular broadband packages' for those on the move.

The best pay as you go deal appears to be Vodafone and 'Top Up And Go,' £39 set-up, £15 per GB top up with the first GB offered free and no 30-day expiration for the data.

T-Mobile 'Pay Per Day,' meanwhile is £24.46 set-up, £2 per day/3GB.

For those wanting a contract, 3 offers mobile broadband for £15 a month when you sign-up to a 24 month contract, with a 15 GB per month limit.

O2, Vodafone, 3, T-Mobile and Orange all offer PC laptops or netbooks as incentive for signing up to a 24 month contract.

O2 prices increase further if you use your iPhone as a modem abroad, £2.94 a MB in the EU and £6 a MB everywhere else.

O2 has said Internet tethering doesn't work on Pay & Go with any handset or older 2G iPhones.

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