JavaScript Syntax Highlighter

http://alexgorbatchev.com/SyntaxHighlighter/

SyntaxHighlighter is a fully functional self-contained code syntax highlighter developed in JavaScript.

The script is meant to help a developer to post code snippets online with ease and without having to worry about applying format. People who use blogs like MovableType, .Text (dotText), dasBlog and any other system can easily add code to their posts.