This WordPress plugin by Allan Collins will allow you to add code snippets to your pages/posts. Suitable for code tutorial sites.
Major overhaul of version 1.0.
Moved code to a reusable code library so that it is no longer limited to one page/post.
Snippets can now be placed anywhere in the post/page’s content.
More than one snippet can be added to a page/post.
One click upgrade feature to upgrade from version 1.
Plugin homepage: http://www.allancollins.net/486/wordpress-code-snippet-2-0/