I haven’t tried this yet but it looks like a nice addition if you plan on typing documents while on the go.  For emails and instant messaging I don’t think it is necessary because you will want to be holding the unit all the time and tapping on the screen to navigate from message to message.

Does any one have this?  If so do you like it?

 

Powerful Mobile Computing on the Go: Meet the BlackBerry Mini Keyboard for the BlackBerry PlayBook «Inside BlackBerry – The Official BlackBerry Blog.