Emacs24 on ubuntu 12.04 LTS

http://devajava.blogspot.in/2012/08/emacs-24-on-ubuntu-1204.html

To add this PPA:
$ sudo add-apt-repository ppa:cassou/emacs
$ sudo apt-get update

Then, for emacs-snapshot:
$ sudo apt-get install emacs-snapshot-el emacs-snapshot-gtk emacs-snapshot

*Or*, for emacs24:
$ sudo apt-get install emacs24 emacs24-el