Emacs 9.0 RC2
Emacs GNUstep is a port of the latest GNU Emacs source to the OpenStep (or NeXTstep) APIs.
It may also work on other GNUstep platforms, including FreeBSD and NetBSD. It probably needs more work to run on Solaris and Windows. On OS X, 10.1 and 10.2 are not supported due to the absence of certain APIs supporting explicit character layout in text rendering. (It might be possible to produce a 10.1/10.2 version that allows only fixed-width fonts.)
On the Mac, this port differs from "Carbon" ports of GNU Emacs in that it makes a more concerted attempt from the ground up to follow OS X desktop and UI conventions (without, however, limiting in any way what you can already do with Emacs). In addition, it runs on non-Mac platforms via the free GNUstep implementation of OS X's Cocoa APIs.