Our dd1 used both hands depending on task (would draw with one but eat with the other for example) when she was one, two, early three. But she did seem to use her left a lot when most kids were primarily using their right. Neither dh or I are left handed. She is left handed (now is almost 7 years old) and we could tell for sure when she was three.
Dd2 is not even 2 1/2 but it is obvious already that she is right handed.
We never made a big deal about it either way (not "oh how cool is that?" or "bummer....") It has not seemed to be a problem for her so far. It took her a little longer to use scissors than most kids as she held them turned really funny but of course she figured it out. She is very good at art, athletics, writing - doesn't seem to factor in for her.