We have been in the process of making some materials for several months now and introducing exercises informally and inconsistently within that time. We have a 3 year old and a 10 month old. I found the book "Teaching Montessori in the Home, The Pre-School Years" by Elizabeth Hainstock useful for making materials but a little unrealistic -- like cutting out those small letter and # stencils to trace onto dark balsa paper (you have to use the back of the paper and make sure the letter# is reversed when tracing so it turns out right). i liked her suggestion for color tablets: going to a paint store and asking for free samples of the colors, then mounting them to poster board or balsa.
the montessori-n-such catalog IS fabulous!
i'd love to hear more details from people about how exercises are being introduced, how the home environment is set up, how a child's interest is captured, how to have 'school' time while a baby is around (since we're often out of the house when the baby does take a nap), etc.