acid@sone:~$ sudo add-apt-repository ppa:ondrej/php5-oldstable
You are about to add the following PPA to your system:
 This branch follows the oldstable PHP packages as maintained by me & rest of the Debian pkg-php team.

NOTE: Ubuntu 13.10 (and higher) won't be supported in the repository.  If you require PHP 5.4 use Ubuntu 12.04.x LTS.

You can get more information about the packages at https://deb.sury.org

It also includes some widely used PHP modules (if you need some other feel free to send me a request via deb.sury.org or via launchpad).

If you need newest PHP 5.5 you can use the main PHP repository:
    ppa:ondrej/php5

BUGS&FEATURES: This PPA now has a issue tracker: https://deb.sury.org/pages/bugreporting.html

PLEASE READ: If you like my work and want to give me a little motivation, please consider donating: https://deb.sury.org/pages/donate.html
 More info: https://launchpad.net/~ondrej/+archive/ubuntu/php5-oldstable
Press [ENTER] to continue or ctrl-c to cancel adding it

gpg: keyring `/tmp/tmpGPzSQj/secring.gpg' created
gpg: keyring `/tmp/tmpGPzSQj/pubring.gpg' created
gpg: requesting key E5267A6C from hkp server keyserver.ubuntu.com
gpg: /tmp/tmpGPzSQj/trustdb.gpg: trustdb created
gpg: key E5267A6C: public key "Launchpad PPA for Ondřej Surý" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)
OK
acid@sone:~$