skype and yahoo both work well enough, but having been on the receiving end of a number of voip calls, i prefer to use calling cards whenever talking to someone important. calling cards typically sell for 30-35% of face value, which is still much more expensive than ex-usa cards, but the quality is very good and $4 will still get you around 38 minutes in talk time. my favorite calling cards are the 17910 unicom cards because they are high quality and can be stored on your phone. never use a calling card from a cell phone because the combined cost of airtime plus the cost of the card isn't much cheaper than simply dialing direct with your cell phone.