One thing you can not take away from the iPad is the almost inexhaustible number of apps, some of which have greatly enhanced the capability and functionality of the device.
Before now, voice calls on your iPad was restricted to VOIP using apps like TEXTFREE WITH VOICE . But now, you do it using your SIM card!
So much has been said about Apple and its EXTREME proprietary restrictions, this can only be the reason why voice and SMS features, using your SIM, were never enabled in the first instance. Many of the enhanced functions on the ipad requires you to have your device “jailbroken” to bypass Apple’s restrictions. Before now, about the only app available that could use your SIM card for messaging was SWIRLYSMS. It is available for free in Cydia store (Cydia is an app store for apps that did not make it to Apple’s app store for varied reasons).
PhoneItiPad is a premium app ($19.99 / N3500) that allows you to use your SIM card to make calls with or without an earpiece. The price is a little steep but i think it is still tempting enough. It is also available in the Cydia app store.
I can bet Apple would block this app in its next release so you may want to consider that before parting with your money.
Will give the app a spin and give a feedback.
Unfortunately, only users of iPad 1 with 3G SIM and IOS 4.3.3 can enjoy this app. Sorry.