Meditation may improve sleep on its own, but in my opinion, meditation primarily improves your ability to stop ruminating. If your primary cause of sleep trouble is that you can’t let go of worries, practice regular meditation. As you learn how to get your mind to be more disciplined, your ability to manage your attention will improve, and you will be able to get yourself to stop ruminating.
Ironically, an anxious urge to get enough sleep is one of the biggest detractors from getting quality sleep. Trust your body to work for you. When you have “should” thoughts such as “I should be able to fall asleep right away,” or “I should be able to sleep for eight quality hours every night,” let these thoughts go. Turn your mind to a meditative relaxation exercise. It’s normal to have disrupted sleep every so often. Jon Kabat-Zinn has created some wonderful meditation CDs [http://www.mindfulnesstapes.com] that are great tools to help you develop meditation as a pathway to increased mental discipline and peace. I highly recommend these.
To summarize, sleep is a crucial leg in our three-legged stool that supports health. Sleep is not just a switch you flip—it can be a delicate balance and routine you need to become attuned to. Respect the balance and the routine. Take time to develop the ability to nourish your whole self with the quality sleep you need in order to fully bloom as the person who you are.