I think the only thing that defines a Montessori is that they follow Maria Montessori's philosophy. They generally have similar educational toys but its the philosophy they share. Have a look around the internet about Maria Montessori and see what you think, if the philosophy rings true to you, you may want to get her into a Montessori playgroup or a Centre. Most Montessori's start at age 3, but you will find the rare one that is before. I know there is a centre in Brisbane that has a nursery and goes up... so they are out there. For the younger ones, they don't often do "Montessori time" because the philosophy is really geared for over 3's.

Goodluck deciding! I had to work and did not have family around, I put my DD into family day care until she was 3 because I preferred the home environment for her.