Force.com IDE

The Force.com IDE is a powerful client application for creating, modifying, testing and deploying Force.com applications.

Based on the Eclipse platform, it provides a comfortable environment for programmers familiar with integrated development environments, allowing you to code, compile, test, and deploy all from within the IDE itself.

http://wiki.developerforce.com/index.php/Force.com_IDE

An Introduction to the Force.com IDE

The Force.com IDE is a powerful client application for creating, modifying and deploying Force.com applications. Based on the Eclipse platform, it provides a comfortable environment for programmers familiar with integrated development environments, allowing you to code, compile, test, package and deploy all from within the IDE itself. Much of the actual work, such as compilation, happens on the Force.com platform—the Force.com IDE performs the communication and result parsing transparently.

The IDE also features an embedded schema explorer for a live view of your database and metadata components. Using the standard synchronization features of the IDE, you can create a project that enables multiple developers to develop against a shared source code repository. This article provides an overview of the Force.com IDE and its features.

http://wiki.developerforce.com/index.php/An_Introduction_to_Force_IDE

Force.com IDE Release Notes

The Force.com IDE provides a unified interface for building and deploying Force.com applications. Designed for developers and development teams, the IDE provides tools to accelerate Force.com application development, including source code editors, test execution tools, wizards, and integrated help. It is currently available as a plug-in for Eclipse 3.5, 3.4 or 3.3.

http://wiki.developerforce.com/index.php/Force.com_IDE_Release_Notes