I find the exact opposite works for me: if I normally go to sleep at midnight and wake up to an alarm at seven (which is not an unusual pattern for me), if I go to bed at 11pm, I tend to wake up between 5am and 6am, well before my alarm. To a point, the earlier I go to bed, the stronger the effect is, so going to bed at 9pm will usually have me up and refreshed at 1am or 2am, and I feel like I've slept "for the night".
My friend and I are starting the Uberman sleep schedule (six 20-minute naps spread evenly throughout each day) tonight. Have other lesswrongians experimented with alternate sleep schedules? Are any of you qualified medical experts who can give input or advice? Success stories and failure stories would both be appreciated, and I'll keep you guys posted on our progress.