I've been using and experimenting with VOIP (voice over the internet) companies for about four years. I make most of my calls to the US and from time to time to Europe. Here are my results:
Best Quality: Skype www.Skype.com. Price: about 2US cents per minute. Note: ALL CALLS TO TOLL-FREE NUMBERS ARE ABSOLUTELY FREE! I use Skype to make my toll-free calls to my bank, Social Security or any company with a toll-free number.
Best Value: Yahoo phone-out. www.voice.yahoo. com . This is the one I use for all my other calls to the US. The price is 1US cent per minute and the quality varies from fair to excellent. You buy $10 credits with a credit or debit card. That's 1,000 minutes!! (16.66 hrs). Toll free numbers are also free.
Best Value to calls to landlines in Israel is www.nymgo.com. I use this England-based company to make my call to Israel and within Israeli landlines at less than one cent per minute! (0.009). You can receive calls on your landline from all over the world! Calls to cell phones are much higher at 8 cents p/mn.
In brief, if money is no object, use Skype, otherwise Yahoo's Phone-out is a great value, along with Nymgo for Israel landline calls.