If you intend to considerably cut down the cost of your mobile calls, here is a list of VoIP services that can allow you to cut down your mobile communication costs to the cheapest it can be so far. You only have to select the right service tailored to your needs, mobile phone type and model, connectivity, etc.
1. YeigoYeigo is here to end paid-for mobile communication as you know it. It is a free software application that can be installed on mobile phones for calls and messages to any mobile or landline anywhere in the world. Calls are free to other mobiles using Yeigo, anywhere they can be in the world. Yeigo works on most recent mobile phones on the market. To use Yeigo, just like many of the applications of its like in this list, you need to have a data connection like Wi-Fi, 3G, GPRS, etc. Read more on Yeigo here.
2. FringFring is also a free application to be installed on a mobile phone for calls and messages. Calls to other Fring others are free, and are paid at cheap rates to landline and mobile networks. The cell phone models on which Fring works is more limited than for Yeigo. However, Fring users can communicate with users of other instant messaging service like Skype, MSN Messenger, ICQ, Google Talk, SIP, Twitter, AIM, Yahoo etc. Fring also requires a data service plan like WiFi, 3G, GPRS etc. Read more on Fring here.
3. TruphoneBy installing the Truphone software on your mobile phone, you can have your mobile phones routed through the Internet,and make free calls to other Truphone users. Calls to plain mobile and landline phones are cheap. Truphone allows you to make calls through Wi-Fi hotspots and your GSM network, which means you can use it really anywhere. It focuses mainly on high-end phone models like the iPhone, BlackBerry devices, Nokia E and N series etc.
4. VopiumVopium is a mobile VoIP service that offers cheap international calls through GSM and VoIP, without necessarily having a data plan (GPRS, 3G etc.) or Wi-Fi connection. If you do have any of the latter, you can make free calls to other users using the same networks. Vopium also offers new users 30 minutes free calls and 100 free SMS for trial.
Packet's MobileTalk here.