Yahoo! has finally announced a separate Yahoo! Messenger for the iPhone platform. This Instant Messaging application is available for 'free' from the Apple's App Store. Earlier, Yahoo! Messenger was usable under the Yahoo! application for iPhone, but under the 'More' option.
With the Yahoo! Messenger application on iPhone or iPod Touch, you can send Instant Messages with emoticons or web links to the online or even offline contacts. If you need to hide your online status, just choose 'Sign in as invisible' at the time of logging in. In special cases, if you know the number of the contact, you can also send an SMS.
The Yahoo! Messenger for the iPhone application is free and can be downloaded through the iTunes App Store or through the App Store on your iPhone or iPod Touch (search for Yahoo! Messenger).