Yahoo! Inc. has just released their Instant messaging application (Yahoo! Messenger) in the AppStore. The application allows users to see online and offline friends and chat with them. Offline friends will get the messages when they go online. It also has the ability to chat with friends who are using Yahoo! messenger on their mobile phone using SMS.
Yahoo! Messenger is available as a FREE download in the AppStore.
Download Now (iTunes Link)
Here are some screenshots: