I've been brushing my daughter's teeth since they first arrived at 5 months. This christmas, (she's one now) she was given a pink colgate electric toothbrush made for little kids and she loves it! I use colgate baby toothpaste too, which has less fluride in it than adult toothpaste, so it doesn't matter if they swallow some. Just use a tiny amount. I've also heard that it helps to give your toddler a toothbrush to brush your teeth while you're brushing theirs. I think it's also important to let them see you brush your own teeth, so they know it's just part of every day life.
Ellie, NSW, DD 3 yrs & TTC # 2