The easiest to use code highlighting ever. Choose between 8 different color themes to highlight your code snippets. Many programming languages are supported.
This plugin lets you embed Github's Gists in your posts or pages, but the main deference is that this plugin also enables you to create Gists without leaving your WordPress.
HighLight Code allows you to add syntax highlighting to the snippets contained in your articles.
NOTE (beta): This plugin is very felt, it is still in development phase!