For people learning regular expressions the resource you really want them to pick up is japhy's YAPE::Regex::Explain which will take a regular expression, break it up, and insert comments telling you how perl will understand what you wrote.
I tried it, tilly. That is great!. It's very easy to use, and I love the plain english explanations. Much more helpful as a teaching aid than what I posted here.
Thanks for the pointer, and thank you, japhy, for the modules!