Install PHP 5.2 on Ubuntu 10.04 Lucid Lynx

There are many reasons why we want to install PHP 5.2 on Ubuntu 10.04 Lucid Lynx, the most prominent is that many web packages are not compatible yet with PHP 5.3. Drupal 6 being a prime example.

But there is no automated method out of the box, and there are now several scripts floating around the Internet that may work or just partially work. A major concern is the ability to update, easily switch to PHP 5.3 when the application is ...