The new IDE is available for Windows, Mac OS X and Linux64.
At the time of writing, the Arduino Pro IDE was at version 0.0.1-alpha-preview which suggests that most users better wait a few releases before downloading and installing the new IDE. Those who prefer to build the IDE themselves from the source code will have to wait too.
In VideoHere is a video showing our first impressions of the new IDE.
The Arduino Pro IDE Has Many New Features
Two Modes, This is Classic Mode
Improved Error Reporting
Built-in Source Control
Click here to download the Arduino Pro IDE.