I read once that someone had managed to achieve getting free phone calls with the Nokia N900 nationally and internationally.

I moved to Australia form the UK about 6 years ago and sitll have a lot of family and friends over there. I was just wondering how this person would have achieved this kind of thing? Is it something which can be changed in the phone settings? Or even a piece of software i would need? If thats the case... would they also need that software for their phone? Ideally i wouldl ike to be able to call land lines abroad for free from my phone but was wondering the cheapest or if not free way to do this? Same as SMS.

Thank you very much!

Mart.