O2 has become the first UK iPhone 4 carrier to break cover with tariffs for the soon-to-arrive fourth iteration of the Apple’s smartphone.

Compare iPhone 4 deals at Top10: iPhone 4 Deals

The original UK iPhone network has unveiled 12 pay monthly contracts for new and upgrading customers, which are split evenly between 12-month and 24-month options. However, these have yet to be tied to prices for the device itself.

The cheapest two-year deal is £25 per month, which entitles takers to 100 call minutes and 500Mb of data per month. Also available are 24-month deals at £30 for 300 minutes and 500Mb and £35 per month for 600 minutes and 500Mb.

Alternatively, there are a number of contracts aimed at consumers with higher web usage requirements. These feature price points of £40 for 900 minutes and £750Mb, £45 for 1200 minutes and 750Mb and a premium contract with a monthly charge of £60 for unlimited calls and a data limit of 1GB.

O2’s 18-month deals are structured in the same way but will cost subscribers £5 per month more for identical monthly calls and data allowances.

Additionally, plans tailored for business users are on offer – in keeping with iPhones finding greater acceptance among a demographic that would ordinarily have opted for a handset from the messaging focused BlackBerry range.

Just hours after O2 detailed its new contract terms, a number of consumers took to Twitter to air their concerns about the removal of unlimited data options that had previously been available with the network’s iPhone deals. As well as iPhones, the carrier is axing unlimited data from all smartphone contracts.

The availability of thousands of iPhone apps to download, coupled with the latest version’s media optimised 3.5-inch super high resolution display, means that a generous web usage allowance is deemed crucial by Apple smartphone users who claim that this is essential to make the most of what the handsets have to offer.

However, O2’s decision to withdraw its unlimited data options from smartphone contracts is expected to be aped by a number of UK networks in weeks to come, as they attempt to discourage a surge in demand. A number of analysts have forecast that the massive take-up of web-enabled devices will cripple 3G networks, with the result that operators will struggle to maintain a good service.

3, T-Mobile, Vodafone are all expected to announce their tariffs imminently and have all launched pre-registration pages on their web presences. Virgin Media, which has never before offered iPhones for sale, is strongly rumoured to be in talks with Apple with a view to adding the handset to its product line.

Unveiled this week by Apple Chief Executive Officer Steve Jobs in a characteristically evangelistic address at the World Wide Developers Conference in San Francisco, the iPhone 4 is expected to break sales records worldwide.

The latest iteration of the handset improves on earlier editions principally thanks to the inclusion of HD video recording, a powerful 1Ghz processor to allow owners to use multiple apps simultaneously and video calling via a secondary front-facing camera.

Available in a choice of black and white and 16GB and 32GB storage options, the handset officially goes on sale in the UK on June 24th. However, pre-orders will be taken by a number of networks from June 15th.

Compare iPhone 4 deals at Top10: iPhone 4 Deals