One way to find out is navigate to the following URL in a browser:

http://packages.ubuntu.com/

try your search there, of course you will need to select the appropriate version your using. This should give you a brief answer if the package is included for your version of ubuntu.

Another easy way is to search on your local system if emacs is available in the PPA

• Open a command line terminal by issuing Ctrl-Alt-T or searching for terminal in the Dash and type

  
  
  

           #sudo apt-get update
  
           #apt-cache search emacs
  
  

This will search all of the packages in the ppa for the words emacs in the title.

According to my response theres a few packages available.

emacs - The GNU Emacs editor (metapackage)

emacs-goodies-el - Miscellaneous add-ons for Emacs

emacs23 - The GNU Emacs editor (with GTK+ user interface)

emacs23-bin-common - The GNU Emacs editor's shared, architecture dependent files

emacs23-common - The GNU Emacs editor's shared, architecture independent infrastructure

emacs23-el - GNU Emacs LISP (.el) files

emacs23-nox - The GNU Emacs editor (without X support)

So essentially you could try to

#sudo apt-get install   

any of the above packages.