This another great news from Yahoo for anyone who had an iPhone. Right now, you can used your iPhone to create Video Call [Using WiFi connections or 3G] and also make Free Voice Call [iPhone to iPhone VoiP Calls] with Yahoo Messenger for iPhone. For some chosen users (in some country, it even can send free SMS via Yahoo Messenger.
Another great thing with this newest YM for iPhone is you can run Yahoo Messenger at the same time you open / run other iPhone Apps [Multi Tasking Supported].
Youtube Video for Yahoo Messenger Video Call / Voice Call on iPhone
Get Yahoo Messenger for iPhone / iPod Touch from iTunes.
Note: you can also add Windows Live Messenger User to your contacts on YM for iPhone