UK newspaper The Guardian has announced a partnership with On2Go to launch a downloadable news application for Guardian readers.

Guardian Unlimited mobile offers the same live news stories that users might find at www.guardian.co.uk, but users can personalise the topics they subscribe to and the order in which they appear. On2Go plans to add other content providers to the service in the next few months.

The service is one of the first on mobile to include graphical advertising with a pioneering "click to callback" option which allows a user to request a callback - or a brochure by email or post - from the advertiser. Other unique features include a "send" function which emails the user the link to the story requested for future reading.

Since the service only downloads articles on request, it uses little data and is relatively cheap to the end user, unlike other similar services which download all articles when the application is opened.

Simon Waldman, Director of Digital Publishing, Guardian Newspapers Ltd, says: 'One of the greatest challenges we face as a publisher is to ensure that our users get the content they want exactly when and where they want it. For this reason, mobile is going to be an increasingly important platform for us in the coming years, and this trial with On2Go is a key element in our mobile strategy.'

James Page, founder of On2Go, said, "With On2Go, your mobile phone evolves to bring you up-to-the-minute news and information wherever and whenever you need it. I congratulate The Guardian on making sure that their readers are amongst the first to benefit."

The service will be free to users during the initial beta test. There is no mention yet of how much the final service will cost, although as with all such services there is also a small data charge levied by each mobile network for downloading the news application and any new content.

For more information about the service and to participate in the beta test, visit the On2Go page on the Guardian's website.