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