Caching is currently a hot topic in the PHP world. Because PHP produces dynamic web pages, scripts must be run and results must be calculated each time a web page is requested, regardless if the results are the same each time. In addition, PHP compiles the script every time it is requested. [...] PEAR's Cache package offers a framework for the caching of dynamic content, database queries, and PHP function calls.
He talks a bit about what kind of methods are included with the package and shows examples of how it works for function call caching, caching the output from the script execution and how to implement your own custom caching extension of the main code to make it even more flexible.