K.D.
My 4 year old still does this in periodic spurts. When he was almost 3 and I was pregnant and then had a new baby I lost my temper a few times (lack of sleep) and snapped at him for waking me up. That didn't work, but combined with:
- a talk to him about how much happier mommy was when she got a good sleep
- pointing out how cranky he was too when he got up too early and
- giving him some pointers on how to know when it was time to wake up and when it was time to roll over and go back to sleep
he finally learned to wake up quietly.
For us, knowing when to wake up is if the sky is not dark anymore and if the clock says 7 on the first number. (We'll be getting him a clock for his room before the sun starts rising early.) I know they have somewhere "clocks" for kids that don't actually have the time on them, but have pictures instead.
Good luck!