Emacs 24.3 was released today. If you're on OS X, the easiest way to check it out is by downloading a build from EmacsForMacOSX.

As for what's new in Emacs 24.3, in true Emacs fashion, we can ask it directly.

M-x view-emacs-news

If you're using Smex M-x will suggest other view-emacs-* commands.

So next time you're wondering about how to do something in Emacs try asking it directly.

M-x info-emacs-manual

Will view the Emacs manual as info pages.