I used this today - and it's awesome! If I had this while studying abroad in Freiburg awhile back, it certainly would have made both my and Chris' lives a whole lot easier. And we probably would have saved a bunch of money on my rented cell phone and our shared phone cards! Not that Skype didn't have this functionality, but it just wasn't free, so of course I didn't use it :)
Just chalk this up as one more reason why I love google.