Our daughter has just moved to NZ - we have bought a skype phone and subscribed to their fixed phone line service.
We now have a Wellington phone number which my daughter can ring at any time and it rings in our house in the UK.
As all local calls in NZ are free, she can ring from home, office, out and about and it doesn't cost her, or us, anything.
We only pay for calls to NZ, so typically we just ask whoever we are ringing to ring us back - it works fantastically.
Cost is about £11 per 3 months. You can do the same with a UK phone number, however they will incur the normal local call charges at the UK end.
It has made keeping in touch with our daughter so much easier - she was at the bank the other day and didn't know what it was she wanted - so she just rang us and we advised her on the spot.
Ain't technology grand