I don't know much about the Montessori method, but it's so incredibly popular and effective, that it seems worthwhile to spend time learning more about it. I'm hoping I can use some ideas or processes in our daily homeschooling experience. I found a scanned version of Dorothy Canfield Fisher's "The Montessori Method" which is used (in probably a newer, updated version) in the training of Montessori teachers. You can read it online or download it here, for free.
Here's also a website with videos and activities that can give you a better idea of the method.
If you've heard of Waldorf, another method, here's a good comparison of the two (it speaks of Montessori and Waldorf preschools in particular, but I think it gives a good overall summary of the methods).