greentext in php

sup /prog/

how do i code a greentext function for my forum?

i managed to do stuff with str_replace for emoticons and shit but im stuck with this greentext thing...

please help

>>5
preg_replace('/^\s*(>.*)/', '<span class="quote">&gt;\1</div>', $post)

the "quote" css class is left as an exercise for the reader interested in web design