Stephen Harris

<p>This plugin allows you to write posts (of any post type) using the Markdown syntax. The plugin converts the Markdown into HTML prior to saving the post. When editing a post, the plugin converts it back into Markdown syntax.</p>
<p>The plugin also allows you to enable Markdown in <strong>comments</strong> and <strong>bbPress forums</strong>. In these instances the plugin adds a toolbar, and preview of the processed Markdown with <a href="http://code.google.com/p/google-code-prettify/" rel="nofollow ugc">Prettify</a> syntax highlighter applied (similiar to that used in the Stack Exchange websites such as <a href="http://wordpress.stackexchange.com/" rel="nofollow ugc">WordPress Stack Exchange</a>).</p>
<p>WP-Markdown stores the processed HTML, so deactivating the plugin will not affect your posts, comments or bbPress forums.</p>


WP-Markdown

Version 1.5.1 of the plugin works almost perfectly.
I'm just waiting for the upcoming 1.6 update (which is in alpha on GitHub) to be pushed, so I can use GitHub Flavor-style codeblocks specifying the exact language.



Waiting for 1.6

Allows Markdown to be enabled in posts, comments and bbPress forums.

princehaku

<p>This is a code prettify plugin using google-code-prettify. click the add-code media button to insert your code. the code higlighting effect will be seen directly in the mce editor.这是一个代码高亮插件  使用google code prettify 安装后在文章发布处点击插入代码按钮即可插入代码   代码高亮效果会直接在mce中预览可见</p>
<p>Related Links:</p>
<ul>
<li><a href="http://3haku.net" rel="nofollow ugc">Plugin Homepage</a></li>
<li><a href="http://code.google.com/p/google-code-prettify/" rel="nofollow ugc">Google Code Prettify</a></li>
</ul>
<p>*This release is compatible with all WordPress versions since 2.0. *</p>
<h3>License</h3>
<p>This plugin is free for everyone! You can use it free of charge on your personal or commercial blog.</p>
<h3>Translations</h3>


google-syntax

This is a code prettify plugin. the code higlighting effect will be seen directly in the mce editor.

WP-Markdown vs google-syntax