Version 4.0 Milestone 3 for MyEclipse Enterprise Workbench for Windows, Linux, and Macintosh for Eclipse 3.1 is now available in the Downloads section. Please see the area titled 'Downloads MyEclipse for Eclipse 3.1'. If you already have one of our previous 4.0 milestones installed, you can update it by downloading the archived update site from the downloads section or selecting Help > Software Updates > Find and Install > Search for updates to installed features...
To get informed as to all of the all the new addtions, please see the "New & Noteworthy" document here:
You'll need a fresh Eclipse 3.1 (RC3, RC4, or final) installation and JDK 1.4.2_05+ or JDK 1.5 on Windows or Mac, and *only* JDK 1.5 on Linux.