This is a book that I have used successfully with my oldest, and am now beginning with my middle child. Using the introduction of sounds, rather than beginning with the names of the letters, this approach gradually teaches the child to sound out the words by putting together the sounds he/she has learned. There are verbal games that teach rhyming, saying the words slowly (as in sounding things out) and then repeating them fast. Each lesson then concludes with handwriting practice. I discovered printable worksheets for these handwriting lessons at Donna Young's homeschool resource website. Her website is a valuable tool in itself for many areas of homeschooling, by the way.
I started using the "100 Lessons" book with my oldest when she was almost 4 years old, and sporadically picked it up and put it away, due to my lack of consistency in homeschooling preschool, and finally finished it when she was a couple months past 5 years old. Now, eager to begin with my 3-year-old, we're just testing the waters with the first few lessons, and I'm not sure how far we'll go before we table it until she's older. You may be able to find this book at your public library to try or preview before buying it. The resource's website is http://www.startreading.com/.