I recently came across this website www.poketalk.com.
This website allows you to place international phone calls for free!
What's the catch? Well... a single phonecall is limited to 10 minutes, and you have 50 phonecalls per month (Tip- you can re-register with a different e-mail address to get extra 50 calls).
Once you place a call, the phone will ring at your house, and when you pick up, the phone will ring at the destination. That way both of you are having incoming calls and won't be charged.
The main difference between this service and www.Jajah.com (another phone-to-phone service), is that you don't have to register a specific number on either side to get the call for free.
So, this is definitely a website I recommend adding to your favorites.