DD has a bike! We got her one with the handle as she can't quite reach the peddles well enough, but she loves it. She hops on and off it herself and I think it is great for her balance.
DS has a smaller 3 wheel bike that he got for Christmas when he was 18 months old. He couldn't pedal it for the first 6 months, but had worked it out by the age of 2. He's only just gotten a bike with training wheels himself about 6 months ago but he's been able to use it from day dot really well. I would assume DD won't be able to pedal until she's about 2&1/2 when she's gotten a little taller.