title: Understanding PHP library installation
body: <p>I'm trying to understand the options and terminology relating to "installing" PHP libraries on a system (Linux/OSX) </p>
  
  <p>Here are some specific points I'm trying to cover:</p>
  
  <ol>
  <li>What does "install" mean when relating to PHP libraries?</li>
  <li>What's the difference between libraries and extensions?</li>
  <li>How does php.ini fit in?</li>
  <li>How does PEAR fit in?</li>
  <li>How do you import/include libraries?</li>
  <li>If I create my own library, what's the best way to package and distribute it?</li>
  </ol>
  
  <p>Thanks- and sorry for the multi-part...</p>