Originally Posted by lhrsfo

I can't give specific options as I'm on an iPhone 4 at the moment (unfortunately) and it is obviously not what you are looking for. However, I can comment on Skype as I use it extensively on my phone. In the US it seems to work with ATT but in the UK it only works on wifi. Its efficacy seems to vary each time they upgrade the App. Currently, it's not so great - the previous version was better. The issue is that it seems slow to wake the phone up - often going to Skype voicemail before the phone rings. I'm not sure if this is the App (as I say, it was better before) or the phone (the iPhone often fails to wake up for regular cell calls also). However, do not assume that a Skype app will be seamless - if you want the phone to work properly you need to get a local SIM. I then simply forward my home number to Skype and forward my Skype to the local SIM.