Having only just moved onto PHP5 I have now discovered the delights of PEAR, the PHP Extension and Application Repository, its a group of packages for PHp that include classes and functionality that you can include into your own applications. Its a great way of cutting down the code required for repetitive tasks, like accessing databases, parsing XML files, validating strings etc. By default PHP after version 4.2 comes with the basic PEAR installation configured. Once its installed its just a simple case of installing the packages you need. The CLI installer is pretty similar to Debians apt-get e.g:

pear install db

is all thats required to install the PEAR package to handle the database connections. Its also possible to install packages directly from .tgz files:

pear install Validate-0.6.1.tgz

installs the latest version of the validator package. Check out