Do you know how to include html code in a wordpress post?
I tried doing things manually - even downloading plugins. But either the code comes out blank or it has extra lines in it - or it "walks out" of the screen.
Just click the tab in the bar "Html Mode" as trigatch wrote. You can't insert HTML into the standard writing view that comes up. Well from my recollections at least.
I actually wrote a handy blog post about getting code to display in WP posts a while ago as I had the same trouble - I was actually trying to display php, but the principle is the same. I found a handy little work around anyway - its a bit of a hack, but worked for me: