Ezz, you will hear different answers to this question. I would start brushing as soon as you can see them, using a child's toothbrush (Colgate have good ones for kids). The kid's toothpastes say they are ok to use at any age I think, but I didn't bother with toothpaste until Jack was nearly two, and a bit eariler with Tom as the taste made it easier to brush his teeth. If you have fluroide in your water, I would delay until 2, here we don't have it so that is their only flouride.

The mechanics of brushing is more important than the toothpaste until about 2, make sure you brush every surface of every tooth - and GL, it's not always easy to do. When they are really young I have found it easiest to do while they are lying down, such as after a nappy change.