well, that's pretty simple. We found this brilliant javascript (and a piece of flash) module.

Here's a list of supported languages and their aliases:

Language Aliases
C++ cpp, c, c++
C# c#, c-sharp, csharp
CSS css
Delphi delphi, pascal
Java java
Java Script js, jscript, javascript
PHP php
Python py, python
Ruby rb, ruby, rails, ror
Sql sql
VB vb, vb.net
XML/HTML xml, html, xhtml, xslt

just change to  the HTML editor and use the following syntax:

<pre name="code" class="c-sharp">
... some code here ...

beware of opening angled brackets, they should be replaced with  &lt;

 you can also use a textarea, than you don´t have to care about angled brackets :

<textarea name="code" class="c#" cols="60" rows="10">
... some code here ...

This is how it looks like (some random c# sample). you can copy to clipboard, print and open a texteditor.

using System;
using System.IO;
using System.Text.RegularExpressions;
using System.Xml;
using CommunityServer.Components;
using Sgml;

namespace ScottWater.CS.Modules
	/// <summary>
	/// Attempts to clean up the FormattedBody
	/// of any IContent. While this is not 100% valid XHTML
	/// it is a very good start (if no exception, it should be
	/// valid XML).
	/// </summary>
	public class XHTML : ICSModule 
		public XHTML(){}

	    public void Init(CSApplication csa, XmlNode node)
	        csa.PrePostUpdate +=new CSPostEventHandler(csa_PrePostUpdate);

        private void csa_PrePostUpdate(IContent content, CSPostEventArgs e)
            SgmlReader reader = null;
            StringWriter sw = null;
            XmlTextWriter writer = null;

if you want it in your blog on this site, pleas ask your admin, he has to edit a file of the blog theme for you.

Thanks Alex, great job!