Sounds a bit mad, but I came across a site that was trying to sell me the idea. I did a bit of searching and apparently it is possible, but I haven't heard of anyone trying it, all bar the website who are charging $35 to show me. Has anyone experienced this?
Not entirely sure what you mean by charging an IPhone with a phone line. How does it work exactly? Did you mean telephone line as in the telephone cable that goes into the plug or it's something else entirely? Actually, why would anyone want to do that when there is a charging cable and usb is everywhere these days.
Yes, it can be done depending on your location and phone wiring. There are wires that deliver power to the phone. These wires could be used as a charging system if they are the right voltage. If so, it would simply be a matter of connecting a phone jack and line to a USB cable getting the correct wiring configuration. This really is a lot of effort when there are other options available. I think the people doing this are trying to make use of the free electricity that powers their phones. If the voltage is not right, some sort of adapter would be needed. While it wouldn't be too difficult to build such a device, it makes connecting into the phone line a lot more difficult. Either way, I wouldn't recommend doing this unless you were absolutely certain you knew what you were doing.