Work-Around Puts Skype on the iPhone
The breakthrough comes from Tom Keating of TMC Labs, and is likely to be more of a proof of concept, as it uses a complex remote control application, and doesn't actually deliver free calls, though they may be cheaper.
Skype Mobile can be used on Windows Mobile phones to make free or cheap calls from Wi-Fi hotspots, but it has not yet been ported to the iPhone. Such a port is probably not a priority with AT&T, the phone operator providing the iPhone, or with Apple, although reviews have found the phone has good Wi-Fi performance.
The Skype-on-iPhone solution is described as a "workaround-around" using a remote control application, SoonR, to remotely use the Skype application running on the user's desktop computer, and make the calls from there.
It's a bit more complicated than that, however.
It dials out from Skype and makes a SkypeOut call to the mobile, conferencing the two calls together. This uses at least one and possibly two paid SkypeOut calls, which in many cases may still be substantially cheaper than dialling direct from the iPhone. For instance, unlimited SkypeOut credits for US dialling can be bought for US$30 per year.