“While WordPress.com doesn’t allow you to use potentially dangerous code on your blog, there is a way to post source code for viewing. We have created a shortcode you can wrap around source code that preserves its formatting and even provides syntax highlighting for certain languages”
http://en.support.wordpress.com/code/posting-source-code/
-code language=”css”-
your code here
-/code-
Note: replace dashes with [ ] brackets.
The following languages are supported:
•actionscript3
•bash
•clojure
•coldfusion
•cpp
•csharp
•css
•delphi
•erlang
•fsharp
•diff
•groovy
•html
•javascript
•java
•javafx
•matlab (keywords only)
•objc
•perl
•php
•text
•powershell
•python
•r
•ruby
•scala
•sql
•vb
•xml
If the language parameter is not set, it will default to “text” (no syntax highlighting).