When it comes to making free VoIP calls using your Android phone, you have a bunch of options. Services like Skype or Fring let you call other users for free, but you've got to remember to fire them up before you start dialing. Instead of using one app for regular calls and another for VoIP, newcomer Bolt replaces your phone's dialer with a one-stop solution for both. Unlike other services that require you to buy credits to make regular calls, the app connects to traditional phones the old-fashioned way -- over your wireless carrier's network. Calls made to other Bolt users are routed over the web for free, and sip a meager 60KB per minute. That means even with FreedomPop's free deal (which includes a paltry 500MB of data), you'd be able to chat with mom for more than 142 hours before getting hammered with overages.

The company hopes to ultimately become a fully formed communication platform, and offer messaging services as well. Long-term that could mean users could pare down on mobile minutes and messaging packages, and instead spring for a slightly larger data package on their mobile bill. Android users can snag the app now from Google Play, and an iOS version is already in the works.