Download the Arduino Software

The open-source Arduino environment makes it easy to write code and upload it to the i/o board. It runs on Windows, Mac OS X, and Linux. The environment is written in Java and based on Processing, avr-gcc, and other open source software.

Download

Arduino 0018 (release notes), hosted by Google Code:

Also available from Arduino.cc: Windows, Mac OS X, Linux (32bit)

Next steps

Getting Started
Reference
Environment
Examples
Foundations
FAQ

Source Code

The source code to the Arduino software can be browsed online or checked out. See the instructions for building the code.

Previous IDE Versions

These packages are not supported any longer by the development team:

Serial Proxy

Also useful is the serial proxy for talking to an Arduino board from Flash or other programs. It forwards data from a serial port to a network connection and vise-versa. Download: Mac, Windows, source