Yahoo! has today launched a new Messenger app specifically for iPad, which enables you to send instant messages and texts as well as share videos and photos from your iPad. Even better than that, the Messenger app also enables you to make free voice and video (iPad 2 only) calls to any of your Messenger friends. Affordable international calls are available via the app for those with a Yahoo! Voice Phone Out account. Another very handy feature that comes with the app is Windows Live Interop, where you can keep all your friends in one place by adding your Windows Live Messenger friends and then IM-ing them directly from within Yahoo! Messenger. The app also supports multitasking, meaning that you can be notified of incoming IMs even when using another app.
Click here to download the free app. If you've already installed the iPhone Yahoo! Messenger app on your iPad simply select “Update” in the App Store to install the iPad-optimised version of the app: Yahoo! Messenger for iPhone, iPod touch, and iPad on the iTunes App Store
Source: Yahoo! Messenger App Brings Video and Voice Calling to the iPad | Yodel Anecdotal