T-Mobile and Three have both started selling the Apple iPhone 4, which means all the UK's major networks now have iPhone 4 deals.

Pricing on Three starts at £30 a month for a 16GB iPhone 4 on a 24-month contract, which costs £99 up-front. The same phone costs £179 on T-Mobile's £30 tariff.

This week's edition of The Fonecast included an except from an interview about Smart Metering and Machine-to-Machine communication with telecoms consultant Ross Catley.

The full interview is now available to download as a special podcast from our website, from our RSS podcast feed and from iTunes.

In recent months there’s been a lot of talk about smart metering and the wider subject of machine-to-machine communications. With well over 100% penetration of mobile phones in the UK, the promise of machines exchanging information over the mobile network offers operators a new opportunity for growth.

To explain more about the technology and the potential, we invited Ross Catley to join us for this week’s edition of The Fonecast. Ross has worked in the utility & telecommunications industries and is now a consultant who advises on smart metering.

Here’s an edited transcript of our interview.

In a special extended interview, Ross Catley speaks to Mark and James about smart metering in the UK. He explains the basics of 'smart meters', talks about the benefits for consumers and discusses the ways this technology will affect the mobile phone industry.

Towards the end of last year, O2 became the first UK network to pass on 90p for every £1 donated to charity by SMS. (The remaining 10% covered network and third party costs). This move was echoed by a number of other network operators.

It's now giving 100% of text donations to UK charities by covering the costs itself.