Sleeping iPhone Apps - Do you use any?

I know there's some threads about lucid dreaming apps, but I haven't found any about normal sleeping habits. I want to know if anyone uses any app that helps you know more about your sleep: best sleeping hours, how many hours you should get, etc., but not any binaural or ambient music apps.

I've been trying Proactive Sleep which simply has an alarm, you set it, and when you wake up you can select whether you'll go back to sleep or stay awake, and it tells you how many hours you've slept and it's supposed to gather data overtime and give you advice, which I haven't been able to get yet because I've only used it for 3 nights.

I saw some sleep cycle apps, but since my iPod is new, and even if I don't move too much in my sleep, I'm cautious to just leave it on my bed all night.

Do you use any similar apps? If so, how?