Melatonin – Thoughts Anyone?

Being the non-sleeper that I am, from time to time I rely on sleep aids to get my night started – some OTC, some prescribed.  The prescribed meds get me to sleep quickly enough but don't do such a good job at keeping me there.  With the OTC products, I started waking up with headaches so I gave those up.  Someone suggested Melatonin.  I took it last night and within 30 mins I was asleep on the couch.  On a side note, I was completely exhausted so I'm not sure if it was a result of the new 'drugs' or just good old fashioned fatigue.  I've read quite a bit about it, but would like to hear from anyone that's had exposure to this supplement.  Anyone?