I for my part have no issues typing on the iPhone. I actually find it very comfortable. If you love the iPhone, but hate to type on the touchscreen you could try the iTwinge. A simple, but kind of interesting accessory for the iPhone that gives you the feel and tactile feedback of a real keyboard.
The iTwinge slides over your iPhone and covers the keyboard area in portrait mode. This alone makes it a no go for me as I use the landscape keyboard when available.
The iTwinge sells for $29.99 and you can pre-order it now. The iPhone keyboard will ship on November 19th.
Mobile Mechatronics, the maker of the iTwinge, already identified their "first customer". It is Steve Ballmer, CEO of Microsoft. Mobile Mechatronics has a little movie on Youtube that explains why Mr. Ballmer would want an iTwinge.