Just paste your stuff in the comment box and then, and this is the important bit, highlight it all with the mouse and click the "CODE" button on the menu (the one that looks like a "pound" sign or "hash mark.")
This will wrap the selected text in CODE tags.
Of course, you can also do this manually by adding [ CODE ] at the beginning of the text and [ /CODE ] at the end (delete the spaces inside the brackets, though. I have to put those in there or the site will interpret them as legitimate tags.)
