We have an old guide that covers the basics of your sleep patterns. It should get you started, at least.
Physiology of Sleep FAQ (Updated Feb. 18/05) - Dreamviews Lucid Dreaming Community & Resource

I think the best way to map out your sleep is to keep track of when you wake up at night. Anytime you wake from a dream, record the time. After a few days or weeks of this, you should have a pretty good idea of your sleep patterns.