On NETTUTS.com today there's a new tutorial talking about something many frameworks make pretty heavy use of - helper functions.

Every workman needs a good toolbox, and web developers are no different. PHP helper functions are designed to speed up and homogenise repetitive tasks, and make your life that much easier. This first tutorial explains how to make link helpers that will improve your methods for adding hyperlinks and mailto links in your web applications.

They give several examples of a helper function (with code) that starts as a simple link creation helper but progresses to allow styling, flexibility and even adding in the ability to use it to create mailto links.