Free calls to anywhere? (PC-to-PC, PC-to-Phone)

I guess most people know what Skype is by now. However, Skype do have a cost associated with it's use, especially when calling a landline or mobile. And most recently, if you are calling Skype over 3G. This become silly, since you're already paying 3G connectivity, so why should there be cost of running Skype over 3G. One way to go around this is to have a jail-broken iphone and have special apps to convince the voip apps that they are talking to Wifi when they really are talking to 3G.

But wait, now there is a new kid on the block, that challenges the Skype paradigm. It's called Callarc . It is supposedly supporting Symbian, iPhone, Android and Windows Mobile devices. I look at the website, and have not seen where to get access to the downloads/apps. Time will tell how CallArc will stack up against all the existing VoIP apps.