I have the soft brush that goes over my finger that I clean K-bugs 9 teeth with every morning after breakfast. I keep it in the kitchen on her bottle drying rack.
I've been using it since about 4 months old when she got her first 2 teeth through.
I have a little toothbrush and I clean Amiah's teeth during bathtime. She gets to hold it herself when I have to take her out of the tub. She loves that!
em has one bottom tooth and another that is getting ready to poke through (but its in the back)
Finn has three teeth and we brush his teeth most nights with one of those baby tooth brushes that you put on your finger - he loves it and opens his mouth wide.
I actually just posted a question about this in the 18-34 pregnancy forum (high traffic). Kylie is also getting her two bottom teeth and I didn't even think about cleaning them until today when I was reading baby updates. I have a soft baby brush that I'll probably use on Kylie's.