How would you like to use your cell phone to call the other side of the world without having to pay exorbitant fees? Or even just call your significant other at their computer while on the train? If you're a heavy Internet chatter or voice talker, you're most likely familiar with the assortment of VoIP programs that let you make phone calls over the Internet for free or for a very low cost.

 

Voice and chat programs like Google Talk and Skype allow users to make calls over the Internet to other people using the same program and to make cheap calls to landline or mobile phones. While it's great to be able to make these calls from your computer, lots of companies understand that you want to be able to keep in touch on the go on your mobile and save on your cell phone bill. Companies like Barablu, fring, Nimbuzz, and Talkster are making it possible to make cheap and good-quality VoIP calls from your mobile.

 

Regardless of which mobile VoIP service you use, you're going to need a data plan. An unlimited data plan costs anywhere from $5.99 per month (T-Mobile) to $24.99 (Cingular). The applications themselves are free to download and--in most cases--use, but all of them require access to the Internet through your mobile. We tested four Internet phone and instant-messaging applications on mobile devices to find out exactly what they had to offer.