Allan Collins

This plugin will allow you to add code snippets to your pages/posts. This is great for code tutorial sites.
<h3>Upgrading</h3>
If you are upgrading from version 1.0, you will see an option on the Code Library page that will allow you to upgrade. As a precautionary measure, be sure to back up your database before doing so.

WordPress Code Snippet

This plugin will allow you to add code snippets to your pages/posts.  This is great for code tutorial sites.

lexn

This plugin has prettify.js copied directly from google-code source browser. So your code will look exactly like it does on google-code. 
CSS is slightly modified to embolden keywords and types.
<h3>License</h3>
See prettify.js for license details (Apache License 2.0). Other files are available under GPLv2.
<h3>Usage</h3>
<pre class="prettyprint"> 
 // Put your code here. 
</pre>
Or with shortcode:
[code] 
 // Put your code here. 
[/code]
<h3>Making Code HTML Safe</h3>
The plugin automatically makes highlighted code html-safe:
<pre class="prettyprint"> 
 Anything that goes here will be quoted to appear on the page as-is. 
 For example: <head></head><body></body> 
</pre>
To avoid quoting your code, add dontquote as the first class.
<pre class="dontquote prettyprint"> 
 Remember to quote manually. 
 For example: &lt;head&gt;&lt;/head&gt;&lt;body&gt;&lt;/body&gt; 
</pre>
<h3>Line Numbering</h3>
Line numbdering can be enabled as follows:
<pre class="prettyprint linenums"> 
 // Put your code here. 
</pre>
If you want to start with a line number 42, you can do the following:
<pre class="prettyprint linenums:42"> 
 // Put your code here. 
</pre>
<h3>Highlighting Lines</h3>
When line numbering is enabled you can highlight one or several lines of code using the highlight class:
<pre class="prettyprint lang-YOURLANG linenums highlight:2,4"> 
 // line 2 
 // line 3 
 // line 4 
</pre>
Alternatively you can highlight one or several code segments:
<pre class="prettyprint lang-YOURLANG linenums highlight:1-3,5-6"> 
 // line 2 
 // line 3 
 // line 4 
 // line 5 
</pre>
Note: This feature is not available when line numbering is disabled.
<h3>Specifying Language</h3>
Most of the time the highlighter will do a good job guessing how to highlight the code. However, to achieve the best result, you should specify the language:
<pre class="prettyprint lang-YOURLANG"> 
 // Put your code here. 
</pre>
Replace YOURLANG with one of the following:
<ul>
<li>aea</li>
<li>agc</li>
<li>apollo</li>
<li>bsh</li>
<li>c</li>
<li>cc</li>
<li>cl</li>
<li>cpp</li>
<li>cs</li>
<li>csh</li>
<li>css-str</li>
<li>cv</li>
<li>cxx</li>
<li>cyc</li>
<li>default-markup</li>
<li>el</li>
<li>fs</li>
<li>go</li>
<li>hs</li>
<li>htm</li>
<li>html</li>
<li>java</li>
<li>js</li>
<li>json</li>
<li>lisp</li>
<li>lua</li>
<li>m</li>
<li>ml</li>
<li>mxml</li>
<li>perl</li>
<li>pl</li>
<li>pm</li>
<li>proto</li>
<li>py</li>
<li>rb</li>
<li>scala</li>
<li>scm</li>
<li>sh</li>
<li>sql</li>
<li>vhd</li>
<li>vhdl</li>
<li>wiki</li>
<li>xhtml</li>
<li>xml</li>
<li>xsl</li>
<li>yaml</li>
<li>yml</li>
</ul>
<h3>Shortcode</h3>
Here is a quick example. All the parameters are optional.
[code lang=”scala” start=”1″ highlight=”1-3,6,10-14″ background=”#C0FFB3″] 
 // Put your code here. 
[/code]
Html quoting can be disabled as follows:
[code quote=”false”] 
 // Put your code here. 
[/code]
The contents of shortcodes is auto-formatted by WP. As a result and tags along 
with some formatting will be lost. If you need to preseve the original formatting use 
html notation instead of the shortcode.
<h3>Please Support</h3>
If you like Prettify GC Syntax Highlighter plugin, please donate a minute of your time and vote for it. Thank you!

Prettify GC Syntax Highlighter

Your code will look exactly like it does on google-code.

WordPress Code Snippet vs Prettify GC Syntax Highlighter