I've been using my iPad to make free phone calls since getting it back in May of this year, though until recently, was only able to make clear calls over 5mbps+ wifi. 3G would allow the call to be initiated or received, however call quality was something short of anything clear.
Enter 4G mobile router. Now with little exception, I am making and receiving calls wherever I go for zilch, zero, zippo, using one of the many great VOIP apps in the app store.
If you have yet to explore this cool option on your iPad, start with an app like Whistle for iPad. If you've got a bluetooth headset, pair it up for the sans-uber geek look, or use the speaker phone/mic combo built in, and hold it anyway you like. Just don't hold it up to your head. That doesn't pass for cool last time I checked.
Is anyone else rocking the VOIP on the iPad?