The Eclipse Foundation is targeting release of Eclipse 3.1 for late June 2005. There have been seven milestone releases of version 3.1 dating back to August 2004. The Eclipse Requirement Council identified six major themes that the technical community will deliver on:

• Scaling Up
• Enterprise Ready
• Design for Extensibility
• Rich Client Platform
• Simple to Use 
• Appealing to the Broader Community

As with previous releases, the Eclipse development team is committed to preserving backward compatibility with previous version of Eclipse. Eclipse 3.1 will be compatible with Eclipse 3.0 for API (contract), Binary (plug in), Source and Workspace. Most of the Eclipse SDK is "pure" Java code and has no direct dependence on the underlying operating system. The 3.1 release of the Eclipse Project is written and compiled against version 1.4 of the Java 2 Platform APIs, and targeted to run on version 1.4 of the Java 2 Runtime Environment, Standard Edition.
Eclipse SDK 3.1 is tested and validated on the following platforms:

• Microsoft Window XP (Win 32) on Intel x86
• Red Hat Enterprise Linux WS 3 (GTK) on Intel x86
• SUSE Linux Enterprise Server 9 (GTK) on Intel x86
• Sun Solaris 8 (Motif) on SPARC
• HP-UX 11i (Motif) on hp9000 PA-RISC
• IBM AIX 5L v5.2 (Motif) on PowerPC
• Apple Mac OS X 10.3 (Carbon) on PowerPC

More information about Eclipse 3.1 can be found Here