Is the iPhone the moleskine of the future?
Jorge Colombo certainly makes it look easy in these sketches of New York City. You can even watch a quicktime movie of each picture, emerging, so to speak.
~~~~
Update: Here is a newer link for Colombo's work at The New Yorker.
Robin Reagler 
This is amazing.
It looks like The New Yorker bought him out. His site is down but you can see many of his sketches on their site.