Back in the old days, when we all were using Visual Studio.NET 2003, we had this cool tool called CopySourceAsHTML. It was a plugin into Visual Studio with which you can copy source into your wysiwyg editor, so your post will have code-coloring.
Just read that the tool by Colin Coller was retwritten for Visual Studio 2005 by Derick Bailey and Jason Haley has put together an installer for it. Download it here. After installation, in Visual Studio 2005, go to Options, Environment, Addin/Macro security and press the "Add…" button. Then go to the installation folder, confirm, restart Visual Studio, select some code and right-click it.