Yahoo Messenger

Yahoo!® Messenger for BlackBerry® smartphones allows you to chat in virtual real-time with your instant messaging IM contacts when and where you want to not just when you're in front of your computer.

-Fast and reliable messaging
-Your contacts  presence updates  e.g.  Available  or  Offline, in virtual real-time
-The ability to customize your own status messages  e.g. Back in 5 mins, On the Phone
-Complete access to your existing Yahoo! Messenger contact list
-The ability to invite multiple users into one conversation
-The ability to make it your own with avatars, emoticons and custom ringtone alerts

For all technical support with Yahoo! Messenger, please visit http://us.blackberry.com/support/software/yahoo.jsp
For billing issues and technical support options related to App World only, please visit http://www.blackberry.com/support/appworld. 
Direct support is unavailable through the “Contact Support” button.