A Guide on Emacs Package System

Emacs package system lets you auto-update and manage emacs packages. It lets you easily see packages available, update to latest version, install/remove packages. So you don't have to manually track what's installed, each package's home page, whether there's new version, etc.

It is bundled with emacs 24 (currently in beta as of 2012-03-05). You can wait for it, Or, you can just install it now and use it. (it wouldn't be a issue when you switch to emacs 24)

emacs packages elpa screenshot
Emacs “list-packages” screenshot

read more at A Guide on Emacs Package System