Writing source code in posts

Hello

I want to know what is the best way to write source code in a post.

I have read about a lot of plugins for display source code. I was considering installing one. But then I came across this entry in the faq

https://faq.wordpress.com/2007/09/03/how-do-i-post-source-code/

I assume this is a new feature. I have just installed the latest version (2.2.3) but this is not working for me. I have tried using the [sourcode] [/sourcecode] tags both inside the editor and by switching to code mode. In both cases I get the tags printed as it is.

Do I need to install a plugin to see the results?

Thanks in advance.
Manu