I wrote up this article about using CSS styles to create the effect of highlighter and red pen underlines. It was in answer to a question in the Web Design section, but nobody ever goes there unless they are looking for help... so I thought it might be worthy of a new thread.
It's a pretty easy effect to add to any of your web pages and make the copy "pop" in the right places. Read the Tutorial: CSS Highlight and Underline Effects
Hopefully you can get some use out of it.