T.S.
Hi Yvonne,
I highly recommend a couple of things: the book "Healthy Sleep Habits, Happy Child" by Marc Weissbluth (the first half is theory, so skip to the second half for the practical application, it's ordered by age for ease of use), and the Good Nite Lite www.goodnitelite.com.
You may need to put him to bed earlier--counterintuitive, I know, but it works!--and give that method a shot (it's all in the book).
My last thought is, it could be a phase. My son (also 2 1/2) goes through phases where he wakes up way early--5:00--and we've changed nothing. That's where the Good Nite Lite comes in handy. I showed it to him, the moon and the sun, and told him several times that when the sun comes up, he may get out of bed. But, when the moon is awake, it is time for him to rest in bed. It worked the very first night!! He doesn't sleep any longer, but he does stay in his room, allowing us to stay in bed until it is truly time to get up.
Good luck with this and the new baby on the way!