A.A.
My son is this way (bed by 8pm and up at 6am). My daughter is the night owl (not sleeping until 9:30-10:00pm and up at around 8am). I have a 9 week old who seems to be an early riser as well...we'll see how that ends up.
I tried adjusting my daughter's schedule for 6 months to get her to bed earlier and up earlier (I'm an early bird...but cannot stay up that late all the time). It didn't work and so I just accepted the fact that I have a late sleeper.
As the kids get older, they'll adjust their sleeping schedules as needed...but it'll be what their bodies need.
Healthy Sleep Habits, Happy Child was a good book.