Scripts and codes in my posts always look sad, gray. I knew there a syntax highliter plugin for dotclear. It works very well and is relatively fast (being in php...).
This plugin uses GeSHi (Generic Syntax Highlighter), a porwerfull and easy library.
The other tools that he lists are: PeclColorer, PEAR TEXT_Highlighter, and Beautifier. Of course, there's always the PHP function highlight_string, but it's also not very full-featured. There are also plugins for other blogs as well, such as PHP Highlighter for Wordpress.