Including code without it executing.

I’m writing an article about iframes, and I am using an iframe plugin to demonstrate. How do I explain how to put in the plugin without executing one – in other words, how do I type [iframe http://webaddress.com 200 800] in a post without it executing.

I have tried [iframe http://webaddress.com 200 800] and it didn’t work. What’s the solution?

Thanks!
Chris