Alternatively
Check out http://backsla.sh/betamax where there are plenty of services listed that give free calls to landlines.
Mines the one with the SIP-configured Nokia E71 in the pocket.
O2 has announced it is going to try some VoIP services, under the brand of O2 Connect, while in America T-Mobile has opened up its Bobsled service to compete with Google Voice. O2 Connect is just a trial run to see how the services work and how users react to them. The trial is invitation only, though those attending Wired …
When you call someone there's terminating call charges from the called parties network..Also the calls would still have to go through the mobile operators network (UMA gateway) and this has to be bought and maintained... You won't have to use it but it's supposed to be of benefit to the user?
Have you forgotten UMA? Orange provide this for anyone with a supported handset and it works beautifully to supplement the signal up here in the frozen north and the dark recesses of our datacenter down south. When wifi is available the phone roams on to this and routes all voice/data/sms traffic over that. It even works abroad so when I am on the office wifi in the US it often switches to UMA at which point I am in the UK for billing purposes.
Logging onto our mobile accounts from Voip, to make and receive calls is a great idea for those of us stuck in big metal buildings all day. Mainly it means we could pick up mobile calls when the signal is poor over wifi on smartphones without having to divert calls.
I am surprised they have not thought of it sooner.