I actually made a similar post over macnn.com. Netphone is the only app I know of that works with OS X. There was for a short time a program from dialpad.com which allowed you to make mac to phone calls, however this capability has sice been removed (You have to pay!). I was researching this very subject and although I have to find a good replacement, I did stuble across some interesting information. Creative has this little VoIP box which is basically an outboard usb DSP prcessor which allows you to plug in a normal phone and place calls over the internet using VoIP. there is no OSX software from creative, however there are open source drivers for FreeBSD available at fobbit.com. Since OSX is based on FreeBSD it may be possible to compile these drivers on OSX. NOw I am no software engineer so my post on Macnn basically asked if what I was proposing were possible and if they could help . I haven't got an answer so I don't know what else to say. At 15 bucks a piece these things are cheap and you can use a normal phone, so i am eager to find out if this could work.
