Downgrading PHP from 5.3 version to 5.2.x on Ubuntu

I'm looking some some way to downgrade php from 5.3 version to 5.2.x on Ubuntu 9.10

From serverfault $pageUsers[$entry.posts[0].author].name

• Remove the php-installation, e.g. with aptitude.

  Get the sources of the required php version, compile and install it.

  From $pageUsers[$post.author].name

• Since 5.2.10 is the version that's normally installed under Karmic, so you should just have to remove your version of 5.3 and possibly undo any changes to /etc/apt/sources.list that you made in order to get it installed.

  From intuited

• check this one out http://mrkandy.wordpress.com/2010/04/16/install-php-5-2-x-in-ubuntu-10-04-lucid/

  From Hexblot