A blog that I love ~ Montessori ici I get to read up on montessori practices AND refresh my French! (It is written in both languages :)
Shadow Puppet Cutouts by Jen Goode
Daily Montessori - great ideas on not just activities to do with kids of certain ages; but how to set up living and play areas to best encourage development of certain skills.
Child sized mop and real life items
Aid to life: lots about childcare for birth to age 3 from a Montessori perspective
Using realistic dinosaur models for hands-on activities is a perfect introduction to paleontology.
26 Questions to Help Kids Know Themselves Better
The three-period lesson is a Montessori method which can help you clearly and easily teach concepts to your preschooler. It could be used to introduce anything from colors to letters to dinosaur names.