We used Bob Books at home. The early books focus on one vowel sound and a couple of consonants at a time. It's small steps, but if you read each night they really start to pick up the sounds. Very phonics driven and it works.
If you start with a baby they will read by age three..
It also makes their memory every good..
My wife is a first grade teacher...
There are probably some pretty good iPad app...we only had books