This is Type Nine, it's an iPhone keyboard that uses the same T9 keyboard that your Nokia 3310 used to have.
Why would you want to download something that died along with the physical keypad? Well the 'why' is actually in the 'how'.
Remember how fast you could type using T9? Well if you happened to be one of those magical sages that could type faster on a keypad than you could on a keyboard then this is the iPhone keyboard you've been waiting for.
With larger buttons and predictive text it combines the old with the new letting you speed write messages to your heart's content.
Along with the classic keypad layout there's some neat new features including a new cursor function, by simply dragging on the '0' you can move the cursor around the message.
So what are you waiting for? It's out now on iTunes for 69 so go forth and relive the old days.