I started brushing my DD teeth at 6 months using a wet cloth. When she started getting her other teeth I went ahead and bought her a toothbrush (stage 1) for babies/toddlers (softer bristles, soft bumper for their tender gums). I also used Weleda Children's Tooth Gel (you can purchase online at drugstore.com, I think Target carries it too, but not sure) - it's an all natural toothpaste free of fluoride, detergents, synthetic fragrances, colours, and other preservatives. She's 2 1/2 now and I still use Weleda. I switched to a children's toothpaste with fluoride but found out that our city water contains a little fluoride already and of course too much is really bad for our LOs.
Also, my DD always watched me brush and floss my teeth in addition to having me wipe hers, so it wasn't that hard to have her get used to the whole process. In fact, she asks for floss whenever she thinks she has something stuck between her teeth and brushing is hardly ever an issue. Start now so that you won't have to fight with her later =)