The name is the Pinger.  It is for sending and receiving voice messages like text.  Dial the number, say the name of the contact or contacts and send your message.  I know for us Sidekick junkies, we can tap a message faster than we can say it!! =)   Where Pinger excels is for sending the same messsage to multiple people!  They also talk about the being able to safely drive and message at the same time.

 Give it a try here