New member here. Just thought I would share my experience with the letter factory DVD. When my son was 14 months old, and knew most of the alphabet we started watching the letter factory DVD. By 18 months he knew all of the letters and all of the sounds and started sounding out words. He was full on reading at 2 ½ years old. I did not use any flash cards, or any reading program at all, in fact I had no intention of trying to teach him to read yet. 
I do not think he would have read so early if we did not have the letter factory DVD.

For those interested in what we did do. We read books to him since birth, and always use the pointer finger so he could follow along and understand what the words I am saying look like.
 I started sign language at 9 months, we sang the ABC’s a few times daily, “usually during diaper change to stop his wiggling”  At 14 months the letter factory DVD, and the fridge letters to go with it,  at 17 months I would write words like mom, dad, cat, on the magna doodle and sound them out for him. He loved the foam tub letters and would put a bunch of the letters lined up and sound them out.  He stayed at this stage for quite a while. Then around 2 ½ he would read most of his usual bed time books to me. Initially, I thought that he just was memorizing them; however, a couple months later I bought a few new books and my jaw hit the floor when he picked them up and read them too!
He is now 4 years old reading at a 2nd grade level.
Every thing we did was fun and engaging and we only did them when he was interested.