For my own son, I read to him daily. I would point to the words, and let him use his echolalia to repeat the words as I pointed to them. This taught him reading by site. To teach phonics, I simply spelled words to him using their sounds and not the letters. CAT wasn't C-A-T. I sounded out the word cat. So he was able to put the phonetic sounds with the letters. After that, I just converted to multi-sensory spelling programs that thought outside the box, like Phonetic Zoo.
Now, my 10 yr old son can read college level books with ease, fully understanding everything he reads. He understands it so well he can paraphrase and summarize what he has read while "teaching" it to someone else.
That's the simplified manner of how we tackled reading with autism. I hope this helps someone else!