Get Arduino Uno Nano Schematic Images. They use the same processor (atmega328p) and hence they both can share the same program. You can watch the following video or read the written tutorial below.
Arduino nano has similar functionalities as arduino duemilanove but with a different package.
The nano is inbuilt with the atmega328p microcontroller, same as the arduino uno. This arduino nano pinout diagram reference is a handy guide for the arduino nano is originally designed by gravitech and has been included as one of the official arduino boards. One big difference between both is the size uno is twice as big as nano and hence occupies more space on your project. The arduino nano is sometimes preferred over the arduino uno when there is limitation on the space constraint.