If you're interested in prototyping in HTML (because, you know, it's the way of the future, and you don't want to get left behind), but don't know where to start, I just wrote a post that you should find helpful:
The Four-Minute* (HTML) Prototype
It shows you how to prototype a web page easily and quickly. And the best bit? You don't need any prior knowledge of HTML or CSS.
Hope you enjoy it,