Everyone knows about Skype for making calls from your computer and devices enabled for voice over internet protocol.

Well there are some competitors:

Expensive to
iChat
Skype
Whistle Phone – it uses your wifi connection to make calls.
it took a few minutes to download and create an account.
With AT&T the service at my house is horrible. So I have installed this app to see how it works.
So far it is still processing the account creation.
There are icons on the bottom for
Bonjour
Recents
URL Entry
Account
About

Whistle Phone – by Vail Systems

Whistle service is a free phone service that allows you to call any US phone number for free from any where in the world. You can also make international calls with our low calling rates, just add to your international pay as you go balance.

Welcome to Whistle

Your Phone Number is

(205) 623-xxxx

With Whistle, you will now enjoy

* Free ad supported calling to anyone in the US
* Pay as you go Ad Free calling to anyone in the world.
* Connecting all your phone numbers to your Whistle number with Whistle Follow Me