If you are looking for an application to make voice and video calls from your iPad 2 , then Yahoo! Messenger is the application you'll need.
With Messenger you can communicate with your contacts no matter if they are connected from an IPAD, a PC or other device. Follow these steps:
Download and install Messenger from the App Store
Once Messenger is installed, its icon will be displayed on the home screen
Tap to launch
Log in: enter your email address, password and press "Enter"
In the left column of the messenger interface you will have your contact list (A yellow button will appear next to the connected ones).
Click on the contact you want to chat with
In the right pane, click the button with a small microphone or Web camera to send the request for voice or video call, respectively (in the latter will activate the front camera in your IPAD)
Simply wait for your contact to accept the request.