Say goodbye to the code tag.
Wordpress.com blogs have a new shortcode to post source code with syntax highlighting.
If you find that you can’t get it to work, make sure that you have typed in the shortcode, and not copied the snippet from the FAQ entry.
When copied, the snippet contains invalid markup. See if you can spot the difference -
sourcecode language='css']...[/sourcecode sourcecode language=’css’]...[/sourcecode