I recently installed a VOIP phone app on my iPod called “Whistle.” Whistle is gives you a free incoming phone number that can be called from other phones, along with free domestic phone calls within the U.S.
Since my Sprint “Simply Everything” phone plan gives me unlimited voice calls within the U.S., I don’t really need the free voice calling feature. However, I installed it because it’s nice to have alternatives available, just in case. Whistle is free. It works, but the call quality is poor.
Nonetheless, a few days ago I found myself unable to use my cell phone, but still needing to make a call. Since I had WiFi available, I remembered I had the Whistle app available and was able to make my call via Whistle without any trouble.
Whistle has poor call quality on my iPod Touch. However, it is a free app and you can make free calls if you are willing to listen to short audio ads just before your call is placed. I like having extra options which can sometimes come in handy, and Whistle worked for me when I needed it to.
Whistle also offers very cheap rates on international calls.
Whistle doesn’t offer the voice quality of Skype, but Skype costs money to place calls to telephones as well as to have an incoming phone number. Whistle offers both of those features for free.