Make VoIP phone calls for free

Voice over Internet Protocol is a technology that I find to be still in a stage of infancy. Nevertheless, this doesn't mean that we cannot take advantage of the benefits it provides us with. One of the most prominent benifits of VoIP is that it's cheaper than traditional phones, especially international calls, because essentially one simply uses the internet to call other people. However, although it might be cheap to call through VoIP, it almost always isn't free. Here are a couple of websites/applications that offer free VoIP services.

1. Gizmo Project - The guys over at Gizmo Project seem to offer a great deal for people who wish to try out VoIP, and allow you to call about 60 countries for free. Of course, they only give you about 40 minutes of time to take, and I presume that the actual time they give you is going to be a lot less but it is free if you wish to give it a go. I'm guessing the business model here is to get people to try it out, and then when they like it, charge them for their premium services.
   
2. Jajah - This is a pretty cool website where you type in your phone number, and then you type in your friend's phone number and the websites enables you to talk to your friend/who ever you want to talk to for free. You might want to take a look at the rates list to verify if the call is free or not.
   
3. Jaxtr - Works just like Jahjah. It connects you to the person that you want to talk to throught the web. Jaxtr also has a web widget which you can use to talk to other people
   
4. Jangl - Works just like Jahjah and Jaxtr, but it's more private and you first have to provide Jangl an email address of the person you wish to reach instead of a phone number. Jangl will then let you send them a voice mail, and if the person accepts it, it'll give that person a local number and send you a local number. You can then use that number to talk to each other.
5. The Pudding - Although this service is in beta and only open to beta testers, it allows you to talk to anyone in the US, completely free. The way they plan to make money is by showing relevant advertisements to you using speech recognition technology. I'm not sure if this would be a successful start up or not, but it will definitely be interesting to use this service.
   

So there you have it. 5 great ways to talk to most people around the world, totally for free! If you know any other services like this, do let me know.