On PHPied.com, Stoyan shares the hacks he made to the Text_Highlighter PEAR package to get it to correctly format JSON-formatted messages.

Today I played with adding a JSON renderer. Useful in case you want to get highlighted source code in your new shiny AJAX app.

He talks about the tweaks he had to make, links to the demo of the script, and givesn an example o fhos you can use this updated version of the highlighting functionality in your scripts.