In addition to the introduction of the iPad, Apple on Wednesday lifted restrictions that previously limited developers from allowing the use of VoIP calls over a 3G network. In the past, VoIP apps had to use a Wi-Fi network in order to make calls. Now, VoIP calls can be made anywhere, using the AT&T 3G network.

One of the first apps to be introduced on the App Store with support for VoIP over 3G is iCall, an app by a company of the same name. As of today, iCall is available for download [iTunes link] with 3G support enabled.

“This heralds a new era for VoIP applications on mobile platforms, especially for iCall and our free calling model,” said iCall CEO Arlo Gilbert.