Do you wish your calls and text messages were free regardless of your location in the world or time zone? Voypi allows iPhone users to do this hassle-free and without any sort of contracts or limitations that many free services require. The only catch is that it only works with users who also have the app installed. Besides the iPhone, the app supports hand sets with Android 2.2 or higher. Blackberry support is also coming soon. Whether your friends have an iPhone or not, doesn't really matter with Voypi.
The service is always connected and running in the background of your device, as long as you are connected to Wi-Fi or 3G. It essentially takes away calling rates from your provider, but does need a connection of some sort. The other minor downside, already mentioned, is that other users you communicate with must also have the app installed.
There are other similar calling and texting apps on the App Store, but Voypi combines both aspects of communication. Unlike other services I personally tried, which includes Text+ and Whistle, Voypi is ad-free and without limitation on how long you can be on the phone in one sitting. You won't be cut off after a certain period of time, which makes this a great app.
The service also works with your address book and is integrated with information provided on these contacts. This means that you will know who is calling and they will know that you are calling them (or inviting them directly to use the service if they don't have it). You can invite anyone in your address book to use it. You do not need to create any sort of account. It's as simple as going into the app and selecting a name to call or invite to the service.
The app is designed to coincide with another mobile carrier or 3G connection of some sort. However, it will make calling from those carriers free for you. This is specially useful for those of you with expensive overseas services. If you live in an area that has free Wi-Fi -- like in Mountain View, CA -- you may get away with relying on this service solely. However, it may be difficult for you even in that situation to rely on it due to the fact you may travel somewhere without a connection. Network connections using 3G have a much larger range. This means that the up is not a total replacement to a contract fee of some sort with 3G coverage. At least for most users.
The app does come recommended for most phone users with expensive minute fees or overseas fees and those who may not have a network connection set up. It is a great alternative to ranking up minutes on your standard plan; but few users can get away using it on its own. The fact it requires the other user you communicate with having the app also installed, complicates this (as well as a connection of some sort). Despite some of these limitations, the app is definitely worth a try; and if it catches on it may be the next Skype.
Voypi is available on the app store for free!