Used it with my 4.5 years old and LOVE it. We did that book and now she's working on the JT First Grade Book.
She started Suzuki Piano level 1 at the same time (she has good ear) and now just started Suzuki Piano level 2.
I have music background (private lessons not music degree), but I think Teaching Little Finger is quite straightforward. It show where the notes are on the keyboard and what fingers to use, so just follow one page at a time and before we knew it, we finished it.
I'd like to recommend Studying Suzuki Piano More than Music. It provides me with all the guidance I needed to teach my daughter piano. And it also has all the technical points and interpretation for all 7 levels of Suzuki Piano Books.
http://www.amazon.com/Studying-Suzuki-Piano-Handbook-Reference/dp/0874875862/ref=sr_1_2?ie=UTF8&s=books&qid=1288859877&sr=8-2
Grace
mom to Gaby (5) SL K, CC, SWR, Piano (JT + Suzuki + Faber)