FAQ How do I upgrade Eclipse IDE?
Run the Update Manager, using Help > Software Updates > Find and Install... > Search for updates of the currently installed features. The Update Manager will visit the Eclipse Web site and offer updates for the features you have installed and allow for easy update from Eclipse 2.1 to 3.0, for instance. You can use the Update Manager to upgrade only between official Eclipse releases.
If you want to upgrade to stable stream releases or even nightly builds, you have to live on the edge. Download a new build from the Eclipse download Web site (http://www.eclipse.org/downloads) and unzip it in a new directory. We strongly recommend against unzipping over your existing Eclipse version as unexpected side effects may occur. Complete upgrade instructions are always included in the Eclipse readme_eclipse.html file included with every build in the readme directory.