One of the attractive, and sticky applications that endears Blackberry owners to their devices is Blackberry Messenger Manager (BBM). It's essentially an instant message application for your smart phone that facilitates texting.
A new version of BBM was just 'leaked' (messenger 5.0) and looks like a significant enhancement. It adds location management to the application, group chat, and facilitates adding new contacts through a neat 'bar code' feature which is integrated with the camera.
To me, the core strength of the BBerry is around its communication (mail and messenger) attributes. This upgrade cements the appeal for current owners, and those interested in having a device maximized for communications. For others, who seek a mobile internet experience, the iPhone just can't be beat.
Here's a nice tutorial on YouTube, posted by Moe Step: