Arduino with ATmega328 - Using
Introduction
Once you've upgraded your Arduino with an ATmega328 or purchased a new Arduino with an ATmega328, you can start using it with your sketches!
Download the latest Arduino
If you haven't already done so, for your particular operating system. Extract it and launch it like normal.
Choose the ATmega328 board
From the Tools menu, then from the Board sub-menu, choose Arduino Duemilanove w/ ATmega328 (even if your board isn't a Duemilanove).
Upload your sketch
Connect your Arduino, make sure the correct port is selected in the IDE (the upgrade doesn't change the port) and click the upload (play) button. When it finishes, look down at the status area and you should see something like Binary sketch size: xxxx bytes (of a 30720 byte maximum).
